SBIR Phase I: Advanced Semitransparent CdTe PV

该小型企业创新研究（SBIR）第一阶段项目旨在通过改善背接触界面来开发超薄CdTe太阳能电池，这有助于将正电荷载流子（空穴）传输到背接触电极中，同时将负电荷载流子（电子）反射到主结，在那里它们被透明导电电极收集。 为实现这一目标，将采取两种相辅相成的办法。 在施加背接触之前，将添加诸如磷的合适的掺杂剂元素以产生重掺杂的p型层。 重掺杂将产生电子反射器并促进空穴传导半导体或金属接触。 第二途径将涉及合适的p型半导体（诸如掺杂有氮或铜的ZnTe）的磁控管溅射沉积。 初步研究表明，厚CdTe层和CdTe晶体的前景。 该项目将把研究扩展到超薄、半透明的CdTe太阳能电池，以验证应用于光伏窗结构的两种方法中的一种或两种方法的功效。该项目的更广泛/商业影响将是为半透明光伏窗提供改进的背接触界面，这将有助于将这些发电窗的效率提高到10%，同时保持良好的透明度。 据估计，美国幕墙玻璃应用的年度市场约为1.5亿平方英尺（1400万平方米）。 用于高层办公楼的增值光伏窗户涂料可以大幅减少太阳能热负荷，同时提供这些建筑物所需电力的主要部分。

This Small Business Innovation Research (SBIR) Phase I project aims to develop ultra-thin CdTe solar cells by improving the back-contact interface, which facilitates the transport of positive charge carriers (holes) into the back contact electrode and simultaneously reflect negative charge carriers (electrons) toward the main junction where they are collected by the transparent conducting electrode. Two complementary approaches will be taken to achieve this objective. Suitable dopant elements such as phosphorous will be added to create a heavily doped p-type layer before applying the back contact. The heavy doping will create an electron reflector and facilitate a hole-conducting semiconductor or metal contact. The second pathway will involve magnetron sputter deposition of suitable p-type semiconductors such as ZnTe doped with nitrogen or copper. Preliminary studies have shown promise with thick CdTe layers and CdTe crystals. This project will extend the studies to ultra-thin, semitransparent CdTe solar cells to validate the efficacy of either or both approaches as applied to PV window structures.The broader/commercial impact of this project will be the potential to provide an improved back-contact interface for semitransparent photovoltaic windows, which will help move these power-producing windows toward 10% efficiency while maintaining good transparency. The estimated annual market for curtain-wall glass applications in the U.S. is about 150 million square feet (14 million square meters). Value-added PV window coatings for high-rise office buildings can provide a substantial reduction of solar heat loads while delivering a major fraction of the electricity needed for these buildings.