硅亚带隙红外光伏响应及宽谱响应晶硅太阳电池研究

由于硅元素的高丰度及环境友好特性、晶硅电池的高性能稳定性、其产业链的成熟性和业已形成的巨大产能，目前晶硅太阳电池占据了光伏市场80%以上的份额。这种统治地位在可预期的将来不会改变。但近年来随着减小光损失、电损失传统方法取得突破性进展，目前晶硅电池最高效率已趋近27%，正逐步靠近晶硅带隙（相应波长1100nm）所限的29-30%的理论效率极限。如何突破效率极限这个天花板，既是学术上的挑战，也是光伏产业进一步发展所需要解决的问题。当前主流电池包括晶硅电池均为“窄谱”光伏响应，即它们的响应范围集中在可见光区域（波长~390-760nm），而占太阳能40%以上的红外光无法被充分利用。本项目即以此为切入点，首先研究一种高效的晶硅亚带隙（波长>1100nm）红外响应电池，在此基础上，研究一种并联叠层的宽谱响应（波长390-2000nm）晶硅电池，为突破现有晶硅电池效率极限提供一种可行的借鉴方案。

Silicon (Si) is highly abundant and environmentally friendly, on the other hand, crystalline Si (c-Si) solar cells are of high efficiency, stable performance and possess mature industrial chain and huge capacity of production. All these make c-Si solar cells dominant in the current photovoltaic (PV) market with an over 80% market share. This dominant position will not be changed in the predictable future. However, due to the continuous effort to reduce optical and electric losses following the traditional methodology, the highest efficiency of c-Si solar cell is now close to 27%, and approaching the theoretical limit of 29-30% for the c-Si solar cell imposed by the c-Si bandgap width (equivalent to λ=1100nm). How to break the efficiency limit is both an academic challenge and a task that should be accomplished for the development of today’s PV industry. At present, mainstream solar cells including c-Si ones are of “narrow band” PV response, with their responses mainly in the visible region (=~390-760nm); the infrared light that takes more than 40% of the sun emission energy has not been well utilized. Aiming at this challenge, in this proposal, we will first study a high-efficiency surface-barrier Si solar cell with sub-bandgap infrared (λ>1100nm) PV response, and then study a broad band (λ=390-2000nm) PV responsive parallel tandem c-Si solar cell. The results of this proposal will offer a feasible approach that can be used to break the theoretical efficiency limit of c-Si solar cell.