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38th European Photovoltaic Solar Energy Conference and Exhibition; 1-6, Dopant-free heterojunction silicon solar cells are fabricated using sub-stoichiometric molybdenum trioxide (MoOx) as passivating as well as hole-selective layer for n-type silicon. The average carrier lifetime obtained for 50 nm MoOx film directly evaporated on both sides of a Si wafer was nearly 100 μs with corresponding implied VOC of 634 mV. In practice, the cells exhibited VOC in the range 590-608 mV and JSC in the range of 30-34 mA/cm2 without texturization and antireflecting coating. The best cell reached efficiency of 13.6% (14.02% effective efficiency). This is almost 6% absolute rise from our earlier report and close to the best efficiencies reported so far employing direct heterojunction between MoOx and Si without any passivation layer. However, post-deposition protection of MoOx layer from ambient conditions holds the key for maintaining high VOC values of these cells as exposure to air showed drastic reduction in their carrier lifetime and accordingly low values of VOC. Although the passivation quality of MoOx alone does not match to that of intrinsic amorphous silicon, this route significantly reduces the processing steps and avoids use of hazardous gases making the process truly cost-effective.

35th European Photovoltaic Solar Energy Conference and Exhibition; 1247-1251, The performance and durability of photovoltaic modules are strongly affected by the physical condition of their component layers, geometry, and mounting conditions. A proper evaluation of sensitivities of each design variable would help us strengthen the key aspects that affect their mechanical durability in various end use environments. Application of finite element analysis to study the stress and temperature distributions under simple static and dynamic conditions have been suggested previously [1]-[4]. This paper presents a comprehensive study of a broad spectrum of module configurations under practical static and dynamic loading conditions. The objective is to provide comparative information about stress distributions and component failure of the modules of Glass-EVA-Cells-EVABacksheet and Glass-EVA-Cells-EVA-Glass configurations with varying glass and frame thickness, loaded in various mounting conditions. In case of Glass - Glass configurations, the variation in behaviour with and without frame has also been studied.

35th European Photovoltaic Solar Energy Conference and Exhibition; 2089-2093, The degradation of photovoltaic modules is dependent on climate conditions in the end-use environments. Conventionally, Köppen-Geiger (KG) climatic classification is used for such studies. But KG classification does not consider the solar irradiance, the most important climate factor regarding the performance of PV technology. This paper proposes a new classification scheme devised specifically by considering the idiosyncrasies of photovoltaic to get a more refined correlation. For classification three parameters - module temperature, strain accumulation caused due to thermal cycling and relative humidity are considered. The analysis is carried out using meteorological data of locations all over the world and 18 classification zones are defined after the analysis of the data.

35th European Photovoltaic Solar Energy Conference and Exhibition; 657-659, Heterojunction carrier selective contact silicon solar cells are fabricated on both, Czochralski and Float-zone silicon wafers. Molybdenum trioxide and titanium dioxide are used as hole and electron selective layers respectively. The main intention of this work is to achieve dopant-free heterojunction solar cells without using intrinsic amorphous silicon passivation and any traditional anti-reflecting coating. Both the metal oxides are tested for their carrier selectivity and surface passivation. Maximum temperature used during entire cell fabrication process was 150°C. The total number of steps involved are limited to seven. The techniques used are well suited for large area fabrication over an industrial scale. Since this route avoids use of toxic and flammable gases, it results in low overall budget, which otherwise involves critical maintenance and safety measures for these gases. Preliminary results are promising showing ~ 8.7% active area efficiency at 1 Sun simulated radiation. Short circuit current density for the best cell exceeded 31 mA/cm2 with open circuit voltage ~ 514 mV. This route has a potential to become a truly cost-effective, low thermal budget, simple and toxic gases-free process for Si cell production without losing on the current efficiency levels achieved.

In this communication we report on the synthesis and charge mobility of highly soluble perylenebisimid derivatives. We show that introduction of alkylester side chains results in compounds combining a high solubility with charge mobilities up to 0.22 cm(2) V(-1) s(-1). These materials are therefore interesting as an electron acceptor for solution-processed organic photovoltaics.