CN102646484B - Preparation method of conductive aluminum paste for silicon-based thin film solar battery - Google Patents

Preparation method of conductive aluminum paste for silicon-based thin film solar battery Download PDF

Info

Publication number
CN102646484B
CN102646484B CN 201210115220 CN201210115220A CN102646484B CN 102646484 B CN102646484 B CN 102646484B CN 201210115220 CN201210115220 CN 201210115220 CN 201210115220 A CN201210115220 A CN 201210115220A CN 102646484 B CN102646484 B CN 102646484B
Authority
CN
China
Prior art keywords
silver
ratio
silicon
aluminium powder
film solar
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN 201210115220
Other languages
Chinese (zh)
Other versions
CN102646484A (en
Inventor
刘明星
张宇
秦健
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CHANGSHU HI-TECH INNOVATION SERVICE Co.,Ltd.
Original Assignee
Nanjing University of Science and Technology Changshu Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing University of Science and Technology Changshu Research Institute Co Ltd filed Critical Nanjing University of Science and Technology Changshu Research Institute Co Ltd
Priority to CN 201210115220 priority Critical patent/CN102646484B/en
Publication of CN102646484A publication Critical patent/CN102646484A/en
Application granted granted Critical
Publication of CN102646484B publication Critical patent/CN102646484B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Abstract

The invention relates to a preparation method of conductive aluminum paste for a silicon-based thin film solar battery. The preparation method provided by the invention comprises the following steps of: at first, preparing an aluminum powder dispersing agent; preparing aluminum powder colloid through surface modification; uniformly stirring the aluminum powder colloid which is subjected to the surface modification with a glass adhesive and an organic solvent; and finally preparing the conductive aluminum paste for the silicon-based thin film solar battery. According to the preparation method provided by the invention, aluminum powder is subjected to the surface modification through copolymerization, so that the prepared aluminum paste has excellent dispersing property and conduction property.

Description

A kind of silicon-based film solar cells preparation method of conductive silver aluminium paste
Technical field
The present invention relates to a kind of conductive silver aluminum slurry, be specifically related to the preparation method that a kind of silicon-based film solar cells is used the conductive silver aluminium paste.
Technical background
Energy crisis and problem of environmental pollution have promoted the fast development of solar cell industry.Solar cell mainly is divided into three major types at present: the one, based on the crystal silicon solar energy battery of monocrystalline silicon and polysilicon silicon chip; The 2nd, silica-base film, copper indium diselenide and cadmium telluride diaphragm solar battery, dye sensitization and other organic solar batteries; The 3rd, comprise novel solar batteries such as quantum well, multipotency band, hot carrier, now also be in the research and development stage.
Crystal silicon solar energy battery has high conversion rate, the production technology comparative maturity, but manufacturing cost is very high, and enterprise needs relying on government subsidy.How reducing the manufacturing cost of solar cell and improving optoelectronic transformation efficiency is the important means that solar cell improves the market competitiveness.The operation principle of silicon-based film solar cells and crystal silicon solar energy battery is identical, just structure is slightly variant, be silicon-based film solar cells substrate need be arranged is support, wherein substrate can be divided into hard substrates (as glass, stainless steel etc.) and flexible substrate (polyimide, metal forming etc.).With the flexible material be the silicon-based film solar cells of substrate tool has great advantage aspect the solar cell cost reducing, can realize Scroll large-scale production, its technology is simple, energy consumption is low, the production efficiency height is the direction of giving priority in solar cell future.
The silicon-based film solar cells structure mainly is made up of substrate, transparent electrode layer, photoelectric conversion layer and dorsum electrode layer.The effect of dorsum electrode layer is to collect the photoelectron that produces because of photovoltaic effect in the photoelectric conversion layer, and these photoelectrons are derived battery, so dorsum electrode layer also is one of the core material that is directly connected to the photoelectric conversion rate of flexible thin-film solar cell.Dorsum electrode layer mainly is made of metal films such as silver, aluminium or metal oxide films such as ITO, ZnO.
Chinese patent (CN 101937933A) discloses a kind of high-viscosity solar cell backplate silver aluminium paste and preparation method thereof, and its component and percentage by weight are: conductive silver aluminium powder 75~85%; Glass glue 2~10%; Organic carrier 5.5~10%.Its preparation method just mixes silver powder, aluminium powder and glass glue, be ground to the outward appearance exquisiteness, evenly add organic carrier again during no particle and stir, adopt the method for this physics limited for the dispersion effect of silver powder and aluminium powder, will certainly reduce the electric conductivity of slurry.
Summary of the invention
The present invention provides the preparation method of a kind of silicon-based film solar cells with the conductive silver aluminium paste in order to solve the silver powder that exists in the background technology and the limited problem of aluminium powder dispersion effect.
For realizing that purpose of the present invention is achieved through the following technical solutions:
The present invention at first makes silver-colored aluminium powder dispersion liquid, make silver-colored aluminium powder colloid through surface modification treatment then, the silver-colored aluminium powder colloid that this surface modification treatment is crossed and glass glue and organic solvent stir, and make silicon-based film solar cells conductive silver aluminium paste at last.
A kind of silicon-based film solar cells conductive silver aluminium paste, its concrete preparation method is as follows:
Step 1: be that 0.05~0.2% gelatin joins in the aqueous isopropanol that concentration is 0.2 mol with mass fraction, stir, be that the salpeter solution regulation system pH value of 0.0001 mol is 2~5 with concentration, wherein gelatin is (0.05~0.2) with the ratio of aqueous isopropanol quality: 1, under ultrasonic dispersion condition, stir on one side, in prepared gelatin solution, add silver powder and aluminium powder on one side, stirred 30~60 minutes, make silver-colored aluminium powder dispersion liquid, wherein silver powder is (0.3~0.5) with the ratio of gelatin solution quality: 1, and aluminium powder is (0.1~0.3) with the ratio of gelatin solution quality: 1;
Step 2: stir on one side, in the prepared silver-colored aluminium powder dispersion liquid of step 1, add methyl ethylene cyclosiloxane monomer successively on one side, the chlorobutadiene monomer, wherein the methyl ethylene cyclosiloxane is (0.5~0.8) with the ratio of silver-colored aluminium powder dispersion liquid quality: 1, the chlorobutadiene monomer is (0.2~0.5) with the ratio of methyl ethylene cyclosiloxane monomer mass: 1, then add emulsifying agent, wherein emulsifying agent is (0.1~0.2) with the ratio of methyl ethylene cyclosiloxane quality: 1, begin to heat up, keep 70~85 ℃ of system temperatures, stirred 30~60 minutes, then add organic acid catalyst and ammonium persulfate initiator, insulation reaction 2~4 hours, wherein catalyst is (0.04~0.1) with the ratio of methyl ethylene cyclosiloxane quality: 1, and ammonium persulfate is (0.5~1.5) with the ratio of methyl ethylene cyclosiloxane and chlorobutadiene monomer gross mass: 1;
Step 3: with the prepared solution of step 2 through vacuum filtration, dehydration, make the silver-colored aluminium powder colloid of surface modification treatment, with this through the silver-colored aluminium powder colloid of surface modification treatment and glass binder, organic solvent mixing and stirring, namely obtain silicon-based film solar cells conductive silver aluminium paste, wherein silver-colored aluminium powder colloid with the ratio of the quality of glass binder is: (5~8): 1, and organic solvent with the ratio of the quality of glass binder is: (0.5~0.8): 1.
Silver powder described in the step 1 and aluminium powder, its average grain diameter are 0.1~0.5 μ m;
Methyl ethylene cyclosiloxane described in the step 2 is trimethyl trivinyl cyclotrisiloxane or tetramethyl tetrem thiazolinyl cyclotetrasiloxane; Described emulsifying agent is polyvinyl alcohol or OPEO; Described organic acid catalyst is DBSA or p-methyl benzenesulfonic acid;
Glass binder described in the step 3 is Bi 2O 3, ZnO, Al 2O 3, SiO 2And TiO 2Mixture; Described organic solvent is butanone or benzinum.
The invention has the beneficial effects as follows:
The present invention use copolymerization method on the organosilicon strand grafting polychlorobutadiene molecule segment, increased the organosilyl degree of cross linking, polychlorobutadiene itself also has good adhesive property simultaneously, further improve the adhesive property between silver-colored aluminium powder colloid and glass binder and the organic solvent, thereby improved the electric conductivity of silver-colored aluminium paste.
2. the present invention is scattered in the reactant of organosilicon and chlorobutadiene in the silver-colored aluminium powder dispersion liquid and carries out polymerization reaction, and this more is conducive to the dispersiveness of silver-colored aluminium powder, thereby improves the conductivity of silver-colored aluminium paste.
Embodiment
The present invention is described in further detail below in conjunction with embodiment.
Embodiment 1
1. 20 gram gelatin are joined in the 100 gram aqueous isopropanols, stir, be that the salpeter solution regulation system pH value of 0.0001 mol is 3 with concentration, under ultrasonic dispersion condition, stir on one side, add 60 gram silver powder and 36 gram aluminium powders on one side in the gelatin solution of gained, mechanical agitation 60 minutes makes modification silver aluminium powder dispersion liquid;
2. get the prepared modification silver of step 1 aluminium powder dispersion liquid 60 grams, stir on one side, Yi Bian add 48 gram trimethyl trivinyl cyclotrisiloxane monomers, 24 gram chlorobutadiene monomers successively, then add 9.6 gram polyvinyl alcohol, begin to heat up, keep 85 ℃ of system temperatures, stirred 60 minutes, then add 4.8 gram DBSA and 108 gram ammonium persulfate initiator, insulation reaction 4 hours, vacuum filtration dewaters, and makes the silver-colored aluminium powder colloid of surface modification treatment.
3. take by weighing 5 grams, 45%~54%Bi 2O 3, 6.5%~9.5%ZnO, 15%~20%Al 2O 3, 6%~9%SiO 2With 7.5%~12.0%TiO 2Homogeneous mixture, be heated to 1000 ℃, be incubated 1 hour, pour in the cold water then and quench, the material ball milling that quenches 3 hours, discharging oven dry, add silver-colored aluminium powder colloid 40 grams of the prepared surface modification treatment of step 2, add 6 gram benzinum mixing and stirring, namely obtain silicon-based film solar cells conductive silver aluminium paste.
Embodiment 2
1. 10 gram gelatin are joined in the 100 gram aqueous isopropanols, stir, be that the salpeter solution regulation system pH value of 0.0001 mol is 2 with concentration, under ultrasonic dispersion condition, stir on one side, add 44 gram silver powder and 22 gram aluminium powders on one side in the gelatin solution of gained, mechanical agitation 60 minutes makes modification silver aluminium powder dispersion liquid;
2. get the prepared modification silver of step 1 aluminium powder dispersion liquid 40 grams, stir on one side, Yi Bian add 24 gram tetramethyl tetrem thiazolinyl cyclotetrasiloxane monomers, 8 gram chlorobutadiene monomers successively, then add 3.6 gram polyvinyl alcohol, begin to heat up, keep 80 ℃ of system temperatures, stirred 45 minutes, then add 1.2 gram p-methyl benzenesulfonic acids and 32 gram ammonium persulfate initiator, insulation reaction 3 hours, vacuum filtration dewaters, and makes the silver-colored aluminium powder colloid of surface modification treatment.
3. take by weighing 6 grams, 45%~54%Bi 2O 3, 6.5%~9.5%ZnO, 15%~20%Al 2O 3, 6%~9%SiO 2With 7.5%~12.0%TiO 2Homogeneous mixture, be heated to 1000 ℃, be incubated 1 hour, pour in the cold water then and quench, the material ball milling that quenches 3 hours, discharging oven dry, add silver-colored aluminium powder colloid 40 grams of the prepared surface modification treatment of step 2, add 4 gram benzinum mixing and stirring, namely obtain silicon-based film solar cells conductive silver aluminium paste.
Embodiment 3
1. 5 gram gelatin are joined in the 100 gram aqueous isopropanols, stir, be that the salpeter solution regulation system pH value of 0.0001 mol is 5 with concentration, under ultrasonic dispersion condition, stir on one side, add 32 gram silver powder and 10 gram aluminium powders on one side in the gelatin solution of gained, mechanical agitation 30 minutes makes modification silver aluminium powder dispersion liquid;
2. get the prepared modification silver of step 1 aluminium powder dispersion liquid 30 grams, stir on one side, Yi Bian add 15 gram tetramethyl tetrem thiazolinyl cyclotetrasiloxane monomers, 3 gram chlorobutadiene monomers successively, then add 1.5 gram OPEOs, begin to heat up, keep 70 ℃ of system temperatures, stirred 30 minutes, then add 0.6 gram p-methyl benzenesulfonic acid and 9 gram ammonium persulfate initiator, insulation reaction 2 hours, vacuum filtration dewaters, and makes the silver-colored aluminium powder colloid of surface modification treatment.
3. take by weighing 6 grams, 45%~54%Bi 2O 3, 6.5%~9.5%ZnO, 15%~20%Al 2O 3, 6%~9%SiO 2With 7.5%~12.0%TiO 2Homogeneous mixture, be heated to 1000 ℃, be incubated 1 hour, pour in the cold water then and quench, the material ball milling that quenches 3 hours, discharging oven dry, add silver-colored aluminium powder colloid 30 grams of the prepared surface modification treatment of step 2, add 3 gram butanone mixing and stirring, namely obtain silicon-based film solar cells conductive silver aluminium paste.
Be enlightenment with above-mentioned foundation desirable embodiment of the present invention, by above-mentioned description, the related work personnel can carry out various change and modification fully in the scope that does not depart from this invention technological thought.The technical scope of this invention is not limited to the content on the specification, must determine its technical scope according to the claim scope.

Claims (4)

1. a silicon-based film solar cells is characterized in that step is as follows with the preparation method of conductive silver aluminium paste:
Step 1: be that 0.05 ~ 0.2% gelatin joins in the aqueous isopropanol that concentration is 0.2 mol with mass fraction, stir, be that the salpeter solution regulation system pH value of 0.0001 mol is 2 ~ 5 with concentration, wherein gelatin is (0.05 ~ 0.2) with the ratio of aqueous isopropanol quality: 1, under ultrasonic dispersion condition, stir on one side, in prepared gelatin solution, add silver powder and aluminium powder on one side, stirred 30 ~ 60 minutes, make silver-colored aluminium powder dispersion liquid, wherein silver powder is (0.3 ~ 0.5) with the ratio of gelatin solution quality: 1, and aluminium powder is (0.1 ~ 0.3) with the ratio of gelatin solution quality: 1;
Step 2: stir on one side, in the prepared silver-colored aluminium powder dispersion liquid of step 1, add methyl ethylene cyclosiloxane monomer successively on one side, the chlorobutadiene monomer, wherein the methyl ethylene cyclosiloxane is (0.5 ~ 0.8) with the ratio of silver-colored aluminium powder dispersion liquid quality: 1, the chlorobutadiene monomer is (0.2 ~ 0.5) with the ratio of methyl ethylene cyclosiloxane monomer mass: 1, then add emulsifying agent, wherein emulsifying agent is (0.1 ~ 0.2) with the ratio of methyl ethylene cyclosiloxane quality: 1, begin to heat up, keep 70 ~ 85 ℃ of system temperatures, stirred 30 ~ 60 minutes, then add DBSA or p-methyl benzenesulfonic acid organic acid catalyst and ammonium persulfate initiator, insulation reaction 2 ~ 4 hours, wherein catalyst is (0.04 ~ 0.1) with the ratio of methyl ethylene cyclosiloxane quality: 1, and ammonium persulfate is (0.5 ~ 1.5) with the ratio of methyl ethylene cyclosiloxane and chlorobutadiene monomer gross mass: 1;
Step 3: with the prepared solution of step 2 through vacuum filtration, dehydration, make the silver-colored aluminium powder colloid of surface modification treatment, with this through the silver-colored aluminium powder colloid of surface modification treatment and glass binder, organic solvent mixing and stirring, namely obtain silicon-based film solar cells conductive silver aluminium paste, wherein silver-colored aluminium powder colloid with the ratio of the quality of glass binder is: (5 ~ 8): 1, and organic solvent with the ratio of the quality of glass binder is: (0.5 ~ 0.8): 1.
2. a kind of silicon-based film solar cells according to claim 1 is with the preparation method of conductive silver aluminium paste, and it is characterized in that: the described silver powder of step 1 and aluminium powder, its average grain diameter are 0.1 ~ 0.5 μ m.
3. a kind of silicon-based film solar cells according to claim 1 is with the preparation method of conductive silver aluminium paste, and it is characterized in that: the described methyl ethylene cyclosiloxane of step 2 is a kind of of trimethyl trivinyl cyclotrisiloxane or tetramethyl tetrem thiazolinyl cyclotetrasiloxane; Described emulsifying agent is a kind of of polyvinyl alcohol or OPEO.
4. a kind of silicon-based film solar cells according to claim 1 is with the preparation method of conductive silver aluminium paste, and it is characterized in that: the described glass binder of step 3 is Bi 2O 3, ZnO, Al 2O 3, SiO 2And TiO 2Mixture; Described organic solvent is a kind of of butanone or benzinum.
CN 201210115220 2012-04-19 2012-04-19 Preparation method of conductive aluminum paste for silicon-based thin film solar battery Active CN102646484B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201210115220 CN102646484B (en) 2012-04-19 2012-04-19 Preparation method of conductive aluminum paste for silicon-based thin film solar battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201210115220 CN102646484B (en) 2012-04-19 2012-04-19 Preparation method of conductive aluminum paste for silicon-based thin film solar battery

Publications (2)

Publication Number Publication Date
CN102646484A CN102646484A (en) 2012-08-22
CN102646484B true CN102646484B (en) 2013-08-21

Family

ID=46659259

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 201210115220 Active CN102646484B (en) 2012-04-19 2012-04-19 Preparation method of conductive aluminum paste for silicon-based thin film solar battery

Country Status (1)

Country Link
CN (1) CN102646484B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102008186B1 (en) * 2017-02-09 2019-08-07 삼성에스디아이 주식회사 Composition for forming solar cell electrode and electrode prepared using the same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010199034A (en) * 2009-02-27 2010-09-09 Dic Corp Conductive paste for solar cell and manufacturing method therefor
CN102248176A (en) * 2011-07-15 2011-11-23 云南铜业科技发展股份有限公司 Preparation method of flake silver powder with low burning loss
WO2012015283A2 (en) * 2010-07-30 2012-02-02 Lg Innotek Co., Ltd. Solar cell and paste composition for rear electrode of the same
CN102407341A (en) * 2011-10-27 2012-04-11 浙江光达电子科技有限公司 surface modified particle diameter mixed silver powder and preparation method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100830871B1 (en) * 2006-10-11 2008-05-21 삼성전기주식회사 Method for surface modification of nondispersible metal nanoparticles and modified metal nanoparticles for inkjet by the same method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010199034A (en) * 2009-02-27 2010-09-09 Dic Corp Conductive paste for solar cell and manufacturing method therefor
WO2012015283A2 (en) * 2010-07-30 2012-02-02 Lg Innotek Co., Ltd. Solar cell and paste composition for rear electrode of the same
CN102248176A (en) * 2011-07-15 2011-11-23 云南铜业科技发展股份有限公司 Preparation method of flake silver powder with low burning loss
CN102407341A (en) * 2011-10-27 2012-04-11 浙江光达电子科技有限公司 surface modified particle diameter mixed silver powder and preparation method thereof

Also Published As

Publication number Publication date
CN102646484A (en) 2012-08-22

Similar Documents

Publication Publication Date Title
CN101271928B (en) Method for producing high-viscosity solar cell front side silver paste and the same
CN102290118B (en) Electronic silver paste and preparation process thereof
CN102779864B (en) Cadmium telluride thin-film battery and manufacturing method thereof
CN101820002B (en) Conductive paste for solar cell and preparation method thereof
CN102054882B (en) Conductive silver paste with grid electrode front of crystalline silicon solar cell and preparation method
CN102139368B (en) High-dispersion silver powder and solar battery electrode conductive silver paste
CN101931014A (en) Conductive slurry for solar battery and preparation method
CN101560059A (en) Aluminum-doped zinc oxide film coating and nano-rod array material as well as preparation method thereof
CN101271929A (en) Leadless solar battery silver paste and method for producing the same
CN107464883B (en) Solar cell
CN102074590A (en) Back contact electrode in cadmium telluride membrane solar cell structure and preparation method thereof
CN103434215B (en) Super-hydrophilic anti-reflection coated glass and preparation method thereof
CN102956283A (en) Novel lead-free sliver slurry for high-efficiency crystalline silicon solar battery as well as preparation and application thereof
CN109215829B (en) Front electrode silver paste and silver powder for solar cell and preparation method thereof
CN107611269B (en) Perovskite photovoltaic composite material for 3D printing molding and preparation method
CN101942281B (en) Organic binding agent for back aluminum paste of silicon-based solar battery and preparation method thereof
CN103031007A (en) Preparation method of nanosilicon dioxide sol coating solution with low volatility
CN102646484B (en) Preparation method of conductive aluminum paste for silicon-based thin film solar battery
CN111129310B (en) Preparation method of perovskite thin film with introduced capsaicin
CN202585426U (en) Crystalline silicon solar cell
CN110350053A (en) Photoelectric material, preparation and the application of the nano-particle modified ZnO nanowire array of CuO
CN113421970B (en) Perovskite solar cell with HCl modified tin dioxide as electron transport layer and preparation method thereof
CN105801877B (en) A kind of high poly chain base semiconductor material of cuprous iodine anion of organic inorganic hybridization
CN115188519A (en) Silver-coated copper-silver paste and preparation method thereof
CN106848069A (en) A kind of new TiO2Nano material and preparation method and purposes

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
C56 Change in the name or address of the patentee
CP02 Change in the address of a patent holder

Address after: Gaogang city in Jiangsu province Taizhou City Road 225300 No. 67

Patentee after: CHANGSHU RESEARCH INSTITUTE CO LTD OF NANJING University OF SCIENCE AND TECHNOLOGY

Address before: The Science Park Research Institute of Jiangsu province Suzhou City Road 215513, Changshou City economic and Technological Development Zone No. 5

Patentee before: CHANGSHU RESEARCH INSTITUTE CO LTD OF NANJING University OF SCIENCE AND TECHNOLOGY

C56 Change in the name or address of the patentee
CP02 Change in the address of a patent holder

Address after: The Science Park Research Institute of Jiangsu province Suzhou City Road 215513, Changshou City economic and Technological Development Zone No. 5

Patentee after: CHANGSHU RESEARCH INSTITUTE CO LTD OF NANJING University OF SCIENCE AND TECHNOLOGY

Address before: Gaogang city in Jiangsu province Taizhou City Road 225300 No. 67

Patentee before: CHANGSHU RESEARCH INSTITUTE CO LTD OF NANJING University OF SCIENCE AND TECHNOLOGY

TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20221018

Address after: Room 208, Science and Technology Innovation Park, Changshu Economic and Technological Development Zone, Suzhou City, Jiangsu Province, 215513

Patentee after: CHANGSHU HI-TECH INNOVATION SERVICE Co.,Ltd.

Address before: 215513 No.5, research institute road, kechuangyuan, Changshu Economic and Technological Development Zone, Suzhou City, Jiangsu Province

Patentee before: CHANGSHU RESEARCH INSTITUTE CO LTD OF NANJING University OF SCIENCE AND TECHNOLOGY