PTB7 gives some of the highest reported efficiencies for polymer:fullerene solar cells due to its extended absorption into the near infra-red and lower HOMO level. Together with our complete package of processing information, PTB7 becomes a quick and easy way to improve device efficiencies. This represents a cost-effective method to increase performance and impact of devices and data for a wide range of OPV related research.

At typical concentrations for spin-coated devices of 10 mg/ml, a standard batch of 100 mg will produce 10 ml of ink - enough to coat 200 of Ossila"s standard sized substrates even assuming 50% ink loss during preparation and filtration. At concentrations of 1 mg/ml (more typical for ink-jet printing and spray coating) up to 100 ml of ink can be produced.

In a standardised reference architecture (using a PEDOT:PSS hole interface and Ca/Al electron interface) we have shown this batch to give a PCE of 6.8% (see data sheet below) and up to 7.4% using PFN. By using new interface materials and architectures PTB7 has been shown to reach efficiencies of 9.2% PCE in the literature [1,2].

The high solubility in a wide range of solvents makes ink preparation and filtration simple, and PTB7 is one of the easiest materials we have ever worked with (simply shake it to dissolve). This also makes it an excellent candidate for a variety of coating techniques including ink-jet printing, spray coating and blade coating.

For information on processing please see our specific fabrication details for PTB7, general fabrication video, general fabrication guide, optical modelling paper on our standard architecture [3], or email us for any additional help and support.

Luminosyn™ PTB7

Luminosyn™ PTB7 is now available.

General Information

Full name	Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b"]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl ]]
Synonyms	PTB7
CAS number	1266549-31-8
Absorption	670 nm (CH2Cl2), 682 nm (film)
Solubility	Chloroform, Chlorobenzene, Dichlorobenzene

Chemical Structure

Usage Details

Inverted Reference Devices

Reference device were made on batch M211 to assess the effect of PTB7:PC₇₀BM active layer thickness on OPV efficiency using an inverted architecture with the below structure. These consisted of the below structure and were fabricated under inert atmosphere (glove box) before encapsulation and measurement under ambient conditions.

Glass / ITO (100 nm) / PFN (6.5 nm) / PTB7:PC₇₀BM (1:1.5) / MoO_x (15 nm) / Al (100 nm)

For generic details please see the general fabrication guide and video. For specific details please see the below condensed fabrication report which details the optical modelling and optimisation of the multilayer stack.

Previously it has been shown that PFN of around 6.5 nm gives optimum performance [1-3,P021] while modelling has shown that an Al back cathode gives higher performance than Ag when used with MoO_x [4].

The PTB7:PC₇₀BM solution was made in chlorobenzene at 25 mg/ml before being diluted with 3% diiodooctane (DIO) to promote the correct morphology.

Active layer thicknesses of 75 nm, 90 nm and 105 nm were chosen corresponding to the lower, middle and upper end of the "thin film" absorption peak of a typical stack as predicted by optical modelling [1]. For each of these thickness a total of four substrates was produced, each with 4 pixels and the data presented below represents a non-subjective (no human intervention) analysis of the best 75% of pixels by PCE (12 pixels for each condition).

An additional two substrates were also prepared with a methanol wash to help remove the DIO as has been reported in the literature to help improve performance[5].

Overall, the maximum efficiency of 7.2% average PCE (7.4% maximum) was found at 75 nm film thickness.

Note 1: Dektak Thickness calibration

We normally calibrate thin films by use of a Dektak surface profiler, however the use of DIO results in an enhanced level of uncertainty in the film as the DIO will take several hours to fully dry under normal conditions and is likely to undergo some slight further shrinkage when placed in vacuum. The DIO can also be removed by baking the substrate on the hotplate at 80°C for about 10 mins which can be useful for doing quick measurements but also drives excess phase separation between the polymer and PCBM making it unsuitable for device work.

Note 2: Effect of epoxy

Due to the very high solubility of the PTB7 it was noted during fabrication that the film changed colour when in contact with the Ossila encapsulation epoxy in liquid form for extended periods indicating that there was some miscibility. Inspection of the active areas underneath the top cathode indicated that the epoxy had not seeped into the active area before curing and device metrics indicate that this did not appear to affect performance. However, we would recommend minimising contact time between the epoxy and PTB7 films before UV curing.

Fabrication

Substrates and cleaning

• Pixelated Cathode ITO glass substrates (S171)
• 5 mins sonication in hot Hellmanex III (1 ml in beaker)
• 2x boiling water dump rinses
• 5 mins sonication in warm IPA
• 2x dump rinses
• 5 mins sonication in hot NaOH
• Dump rinse in boiling water
• Dump rinse in water
• Stored in DI water overnight and until use

PFN Solution

• Acetic acid dissolved 1:9 in methanol to make stock solution
• 2 μl/ml (0.2 v%) solution of acetic solution in methanol made by diluting the stock solution by 50 times in methanol
• PFN dissolved in the 0.2 v.% acetic acid solution at 2 mg/ml
• Stirred for 30 mins
• Filtered through 0.45 µm PES filter

PFN Test Films

• PFN Test film initially spun at 500 rpm and gave 20 nm
• Second test film spun at 1000 rpm and gave 16 nm
• Thickness was extrapolated to 6.5 nm at 6000 rpm

Active Layer Solution

• Fresh stock solutions of PTB7 (M211) made on at 10 mg/ml in chlorobenzene (CB) and dissolved with stir bar for 1 hour
• Mixed 1:1.5 with dry Ossila 99% PC70BM to make overall concentration of 25 mg/ml and dissolved with stir bar for 1 hour
• Old stock solution of 1,8-Diiodooctane mixed 1:1 with CB to make measuring out small quantities easier
• DIO/CB mixture added to solution to give overall DIO amount of 3%

Active Layer Test Films

• Test film spun at 1000 rpm for 2 mins using unfiltered solution and dried using methanol before Dektak
• 1000 rpm gave approximately 85 nm

Active layers

• Devices spun using 30 μl dynamic dispense (20 μl gave only moderate wetting/coverage)
• Non methanol devices spun for 2 mins
• Methanol devices spun for 30 seconds, then coated with 50 μl methanol by static dispense then spun at 2000 rpm for 30 seconds.
• Cathode wiped with CB
• Vacuum dried in glove box antichamber for 20 mins

Evaporation

Left in chamber over the weekend and evaporated with the below parameters.

• 15 nm MoO_x at 0.2 Å/s
• 100 nm Al at 1.5 Å/s
• Deposition pressure

Encapsulation

• As standard using Ossila encapsulation epoxy, 30 mins UV in MEGA LV101

Measurements

• JV sweeps taken with Keithley 237 source-meter
• Illumination by Newport Oriel 9225-1000 solar simulator with 100 mW/cm² AM1.5 output
• NREL certified silicon reference cell used to calibrate
• Lamp current: 7.8 A
• Solar output at start of testing: 1.00 suns at 25°C
• Solar output at end of testing: 1.00 suns at 25°C
• Air cooled substrates
• Room temperature at start of testing: 25°C
• Room temperature at end of testing: 25°C
• Calibrated aperture mask of size 0.256 mm²

Standard (Non-inverted) Reference Devices

Reference device were made on batch M211 using a standardised architecture for comparative measurements using Ossila standard substrates and materials. These consisted of the below structure and were fabricated under inert atmosphere (glove box) before encapsulation and measurement under ambient conditions.

Glass / ITO (100 nm) / PEDOT:PSS (30 nm) / PTB7:PC₇₀BM (variable) / Ca (2.5 nm) / Al (100 nm)

For generic details please see the fabrication guide and video. For specific details please see the below condensed fabrication report and also Watters et al. [3] which details the optical modelling and optimisation of the multilayer stack.

For this standard reference architecture an average PCE of 6.6% was achieved for the optimised thickness with a peak efficiency of 6.8%. Note that no other optimisation was performed (blend ratio, DIO concentration, drying conditions etc) and so further small improvements may be obtained by varying these conditions and significant improvements obtained by using alternative interface materials [1,2].

Note 1: Dektak Thickness calibration

We normally calibrate thin films by use of a Dektak surface profiler, however the use of DIO results in an enhanced level of uncertainty in the film as the DIO will take several hours to fully dry under normal conditions and is likely to undergo some slight further shrinkage when placed in vacuum. The DIO can also be removed by baking the substrate on the hotplate at 80°C for about 10 mins which can be useful for doing quick measurements but also drives excess phase separation between the polymer and PCBM making it unsuitable for device work.

Note 2: Effect of epoxy

Due to the very high solubility of the PTB7 it was noted during fabrication that the film changed colour when in contact with the EE1 encapsulation epoxy in liquid form for extended periods indicating that there was some miscibility. Inspection of the active areas underneath the top cathode indicated that the epoxy had not seeped into the active area before curing and device metrics indicate that this did not appear to affect performance. However, we would recommend minimising contact time between the epoxy and PTB7 films before UV curing.

Fabrication

Substrates and cleaning

• Pixelated Cathode substrates (S171)
• 5 mins sonication in hot Hellmanex (1 ml in beaker)
• 2x boiling water dump rinses
• 5 mins sonication in warm IPA
• 2x dump rinses
• 5 mins sonication in hot NaOH
• Dump rinse in boiling water
• Dump rinse in water
• Stored in DI water overnight and until use

PEDOT:PSS layer preparation

• Clevios AI 4083
• Filtered into vial using 0.45 μm PES filter
• Spun 6000 rpm for 30 seconds (30 nm)
• Dynamic dispense of 20 μl using pipettor
• IPA cathode strip wipe and labelled
• Put straight onto hotplate at 160°C as soon as cathode wiped and labelled
• Transferred to glove box when all samples spun.
• Baked in glove box at 150°C for 1 hour

Active layer Solution Preparation

• Fresh stock solutions of PTB7 at 10 mg/ml in CB and shaken to dissolve
• Mixed 1:1.5 with dry Ossila 99% C70 PCBM to make overall concentration of 25 mg/ml
• 1,8-Diiodooctane mixed 1:1 with CB to make measuring out small quantities easier
• DIO/CB mixture added to solution to give overall DIO amount of 3%

Active layer spin casting

• Devices spun for 2 mins using 25 μl dynamic dispense
• Cathode wiped with chlorobenzene
• Left to dry in glove box for 2 hours but colour indicated they were still slightly wet
• Dried in vacuum in glove box antichamber for 10 mins to remove DIO

Evaporation

Left in chamber over the weekend and evaporated with the below parameters.

Material	Ca
Base pressure	8.0 E-8 mbar
Dep start pressure	1.7 E-7 mbar
Max pressure	2.7 E-7 mbar
Thickness	2.5 nm
Rate	0.2 Å/s

Material	Al
Base pressure	7.0 E-8 mbar
Dep start pressure	6.0 E-7 mbar
Max pressure	7.0 E-7 mbar
Thickness	100 nm
Rate	1.0 Å/s

 Encapsulation

• As standard using Ossila encapsulation epoxy, 30 mins UV in MEGA LV101

Measurements

• JV sweeps taken with Keithley 237 source-meter
• Illumination by Newport Oriel 9225-1000 solar simulator with 100 mW/cm² AM1.5 output
• NREL certified silicon reference cell used to calibrate
• Lamp current: 7.8 A
• Solar output at start of testing: 0.99 suns at 25°C
• Solar output at end of testing: 1.00 suns at 25°C
• Air cooled substrates
• Room temperature at start of testing: 21°C
• Room temperature at end of testing: 21°C
• Calibrated aperture mask of size 0.256 mm²

MSDS Documentation

PTB7 MSDS sheet

Pricing

Batch	Quantity	Price
M0211A1	100 mg	£297.00
M0211A1	250 mg	£594.00
M0211A1	500 mg	£1010.00
M0211A1	1 g	£1820.00

Batch Information

Batch No.	Mw	PDI	Stock Info
M211	18,000	1.75	Discontinued
M212	> 40,000	2.0	Discontinued
M213	85,000	2.0	Discontinued
M214	322,236	4.12	Discontinued
M215	125,821	2.02	Discontinued
M216	78,852	2.62	Discontinued
M0211A1	234,770*	2.82	In stock

*See impact of polymer molecular weight on performance of organic photovoltaics for PTB7.

Literature and References

1. Enhanced power-conversion efficiency in polymer solar cells using an inverted device structure Zhicai He et al., Nature Photonics, V 6, p591–595 (2012).
2. Simultaneous Enhancement of Open-Circuit Voltage, Short-Circuit Current Density, and Fill Factor in Polymer Solar Cells Zhicai He et al., Advanced Materials, V 23, p4636–4643 (2011).
3. Optimising the efficiency of carbazole co-polymer solar-cells by control over the metal cathode electrode Darren C. Watters et al., Organic Electronics, V 13, p1401–1408 (2012)
4. Designing ternary blend bulk heterojunction solar cells with reduced carrier recombination and a fill factor of 77%, N. Gasparini et al, Nat. Energy, 16118 (2016); doi:10.1038/nenergy.2016.118 (Ossila PTB7 was featured in this paper).
5. Efficient solar cells are more stable: the impact of polymer molecular weight on performance of organic photovoltaics, Z. Ding et al., J. Mater. Chem. A, 4, 7274-7280 (2016); doi: 10.1039/C6TA00721J.

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To the best of our knowledge the technical information provided here is accurate. However, Ossila assume no liability for the accuracy of this information. The values provided here are typical at the time of manufacture and may vary over time and from batch to batch.

关于奥西拉 Ossila由有机电子研究科学家于2009年成立，旨在提供组件，设备和材料，以实现智能，高效的科学研究和发现。十多年来，我们很自豪能向全球80多个国家/地区的1000多个不同机构提供产品。 凭借在开发有机和薄膜LED，光伏和FET方面数十年的学术和工业经验，我们知道建立可靠，高效的器件制造和测试过程需要花费多长时间。因此，我们开发了相关的产品和服务包-使研究人员能够快速启动其有机电子产品开发计划。 奥西拉保证 全球免费送货 合格的订单可免费运送到世界任何地方 快速安全调度 通过安全跟踪的快递服务快速配送库存物品 质量保证 由所有设备的免费两年保修提供支持 清除前期定价 超过30种货币的清晰定价，无隐藏成本 大订单折扣 保存超过订单8％ $ 10,300.00和10％以上的订单 $ 12,900.00 专家支持 我们内部的科学家和工程师随时准备为您提供帮助 全球信赖 优质的产品和服务。已经向很多人推荐。 卡尔加里大学Gregory Welch博士 优质产品价格合理的客户友好公司！ Shahriar Anwar，亚利桑那州立大学 奥西拉团队 David Lidzey教授-主席 作为谢菲尔德大学的物理学教授，David Lidzey教授领导该大学的电子和光子分子材料研究小组（EPMM）。David在其职业生涯中，曾在学术和技术环境中工作，主要研究领域包括混合有机-无机半导体材料和器件，有机光子器件和结构以及溶液处理的光伏器件。在整个学术生涯中，他撰写了220多篇同行评审论文。 James Kingsley博士-董事总经理 James是Ossila的联合创始人兼董事总经理。他拥有量子力学/纳米技术博士学位，并在有机电子领域拥有超过12年的经验，他在有机光伏制造产能方面的工作导致了Ossila的成立并建立了强大的指导精神：加快科学发现的步伐。James对开发创新的设备以及改善可溶液加工的光伏和混合有机-无机设备新材料的可及性特别感兴趣。 Alastair Buckley博士-技术总监 Alastair是谢菲尔德大学的物理学讲师，专门研究有机电子学和光子学。他还是EPMM研究小组的成员，致力于研究功能有机材料的内在优势并将其应用到一系列光电设备中。Alastair的经验并非仅在学术界获得。他曾领导MicroEmissive Displays的研发团队，因此在OLED显示器方面拥有丰富的技术经验。他还是Elsevier的“有机发光二极管”的编辑和撰稿人。 我们的研究科学家 我们的研究科学家和产品开发人员在材料的合成和加工以及设备的制造和测试方面拥有丰富的经验。奥西拉（Ossila）的愿景是与学术界和工业界的研究人员分享这一经验，并提高他们的研究效率。通过提供无需费力设备制造过程的产品和服务，以及能够进行准确，快速测试的设备，我们就可以使科学家们腾出时间专注于他们最擅长的工作-科学。 客户服务团队 客户服务团队负责奥西拉的客户旅程。从创建和提供报价到采购和库存管理，客户服务团队致力于提供一流的客户服务。客户服务团队成员的日常职责包括处理客户订单和价格查询，回答客户查询，安排包裹运输以及将订单更新通知客户。 合作与伙伴关系 请联系客户服务团队以解决所有疑问，包括有关Ossila产品的技术问题或有关制造和测量过程的建议。 位置及设施 奥西拉（Ossila）设在谢菲尔德阿特克利夫（Attercliffe）的Solpro商业园区。 我们在现场运营一个专门建造的合成化学和设备测试实验室，在这里制造我们所有的高纯度，批次特定的聚合物和其他配方。此外，设备制造集群内的专用薄膜和有机电子测试与分析工具套件也位于谢菲尔德EPSRC国家外延设施的1000级无尘室中。 我们所有的电子设备均在现场制造。