Low cost integrated PV in double glazed windows using CdTe bifacial solar cells

该项目的目的是将薄膜光伏层应用于双层玻璃单元的内表面，该单元具有从平均窗户提供高达50 W功率的潜力。初步研究表明，这是可能的，使用高效的CdTe吸收剂沿着TCO接触。需要所有合作伙伴参与进一步的设计工作，将其与红外反射涂层集成在一起。双面CdTe太阳能电池技术使薄膜太阳能电池有机会用于建筑一体化光伏（BIPV）。在当前的太阳能电池设计中，相对厚的CdTe层在充当前接触的TCO涂覆的玻璃衬底上的“覆层”配置下生长，而基于金属合金的不透明层充当后接触。然而，使用拉夫堡的专利工艺，可以获得与p-CdTe层的欧姆接触，从而实现双面CdTe太阳能电池。BIPV应用的另一个重要要求是生长<1微米的高质量CdTe层。这种厚度的层是半透明的，但仍有可能吸收超过90%的入射光子。使用脉冲直流电源以及AML的专利闭合场磁控溅射工艺，可以在低温和高速率下沉积致密的CdTe层，厚度精度仅为亚纳米，仅需使用时间。这种厚度精度对于优化吸收体效率沿着光学透明度至关重要。皮尔金顿公司将利用其在光学建模方面的专业知识，将其世界一流的facitashes用于器件层的结构表征沿着。与奥雅纳一起，他们将有助于开发一个双层玻璃光伏窗原型作为项目交付。该项目将分为7个工作包（WP）。它们是：WP 1。将进行材料和光学设计工作，以优化光伏电池堆（Pilkington/AML/CREST/ARUP）的透明度和发电量。将对堆栈进行重新优化，以包括红外反射器涂层（Pilkington/ARUP）[0-8个月] WP 2的效果。合适的前接触低成本TCO涂层玻璃基板将由Pilkington提供，并由CREST [0-6个月] WP 3进行评估。AML将设计和建造一个具有4个磁控管位置的研发批式溅射系统。最初的单层工艺优化将在AML [ 0-12个月]进行。WP 4研发系统将转移到CREST。CdTe将沉积在Pilkington提供的30 cm x 10 cm TCO涂层玻璃上。在此之前，在“覆层”配置下，将使用化学浴或溅射沉积技术沉积CdS缓冲层。（CREST/AML）[12-28个月] WP 5。纹理TCO背接触将沉积在超薄碲化镉在拉夫堡后，适当的专利表面准备（CREST/AML）[22-28个月]。WP 6。使用互连单元组件的小型双层玻璃窗单元将由CREST和Pilkington联合制造，并接受严格的性能测试（ARUP）[25-36个月]。通过调整透射率，玻璃将有可能控制不必要的太阳能增益，从而减少建筑物的空调负荷。（CREST/ARUP/Pilkington）[30-36个月] Mikkel Kragh博士被ARUP提名为项目经理。将根据TSB指南，通过季度会议对项目进行控制。研究助理将负责CREST太阳能电池器件层的工艺开发和优化，他的工作将由Ayodhya Tiwari教授和Hari Upadhyaya博士监督。Michael Walls教授将监督AML的工艺开发活动，而Paul Warren博士将负责Pilkington的涂层和分析活动。

The aim of this project is to apply a thin film photovoltaic layer on to the inside face of a double glazed unit with the potential to supply up to 50W of power from the average window. Initial studies show that this is possible using highly efficient CdTe absorber along with TCO contacts. Further design work involving all the partners is required to integrate this with coatings for infra-red reflection.The bifacial CdTe solar cell technology allows the oppportunity for thin film based solar cells to be used in building integrated PV (BIPV). In current solar cell designs, relatively thick CdTe layers are grown under 'superstrate' configuration on a TCO coated glass substrate acting as a front contact while a metal alloy based opaque layer acts as the back contact. However using the patented process from Loughborough, it is possible to obtain ohmic contact with p-CdTe layer thus enabling bifacial CdTe solar cells. Another important requirement for the BIPV application is the growth of ultrathin <1 micron layers of high quality CdTe. A layer of this thickness is semi-transparent but still has the potential to absorb over 90% of incident photons. Using pulsed dc power together with the patented Closed Field magnetron sputtering process from AML, dense layers of CdTe will be deposited at low temperature and at high rates with a sub-nanometre thickness precison based on the use of time only. This thickness precision will be crucial to optimise absorber efficiency along with optical transparency. Pilkingtons will extend the use of their world class facitlities for structural characterisation of device layers along with their expertise on optical modelling. Together with Arup they will be instrumental in developing a double glazed PV window prototype as a project deliverable..The project will be divided into 7 Work Packages (WP). These are as follows:WP1. Materials and optical design work will be carried out to optimise the transparency, and power generation of the photovoltaic stack (Pilkington/AML/CREST/ARUP). The stack will be re-optimised to include the effect of the infra-red reflector coating (Pilkington/ARUP) [0-8 months]WP2. A suitable front contact low cost TCO coated glass substrate will be supplied by Pilkington and evaluated by CREST [0-6 months]WP3. An R&D batch sputtering system with 4 magnetron positions will be designed and built by AML. Initial single layer process optimisation will be carried out at AML [ 0-12 months].WP4 The R&D system will be transferred to CREST. CdTe will be deposited on 30cm x 10cm TCO coated glass supplied by Pilkington. Prior to this under 'superstrate' configuration a CdS buffer layer will be deposited using chemical bath or sputter deposition technique. (CREST/AML)[12-28 months]WP5. The textured TCO back-contact will be deposited on ultra-thin CdTe at Loughborough following a suitable patented preparation of the surface(CREST/AML)[22-28 months].WP6. Small scale double glazed window units using the interconnected cell assembly will be fabricated jointly by CREST and Pilkington and subjected to rigorous performance tests (ARUP)[25-36 months].WP7. By adjusting the transmission, the glazing will have the potential to control unwanted solar gains, thus reducing the air conditioning loads of buildings. (CREST/ARUP/Pilkington)[30-36 months]Dr Mikkel Kragh has been nominated by ARUP to act as project manager. The project will be controlled using quarterly meetings in line with TSB guidelienes. A Research Assistant will be responsible for the process development and optimisation of solar cell device layers at CREST and his work will be supervised by Prof. Ayodhya Tiwari and Dr. Hari Upadhyaya. Prof. Michael Walls will supervise AML's process development activities while Dr. Paul Warren will be responsible for coating and analytical activities at Pilkington.