界面工程及掺杂调控实现高效溶液法加工纳米晶太阳电池研究

Back contact plays a key role in nanocrystalline solar cells, because of the high work function of cadmium telluride, traditional metals can not form good ohmic contact with it, so it is very important to develop new interface materials. Due to the self-compensation effect, the hole concentration of cadmium telluride thin film is very low, so it is necessary to doping the film properly in order to obtain good device performance. However, there are few reports on the doping of nanocrystalline films. It is not clear how to achieve the effective doping of CdTe nanocrystalline films. This study is based on the work of nanocrystalline solar cells for many years. A new cross-linked conjugated polymer with adjustable work function was designed and synthesized as a hole transport material for nanocrystalline solar cells to regulate the efficiency of carrier collection at the interface. At the same time, Cu and other doping elements are introduced into the active layer to reduce the series resistance of the battery. Through the overall optimization design of the device, an efficient nanocrystalline solar cell device with conversion efficiency of more than 13% is obtained. It lays a foundation for its commercial application.

背接触对于纳米晶太阳电池起关键作用，由于碲化镉功函数高，传统的金属均不能与之形成良好的欧姆接触，发展新的界面材料具有十分重要的意义。同时，由于自补偿效应，碲化镉薄膜的空穴浓度很低，必须对薄膜适当掺杂才能获得好的器件性能，但是对于纳米晶薄膜的掺杂目前报导很少，如何实现碲化镉纳米晶薄膜的有效掺杂，尚不清楚。本研究拟在多年纳米晶太阳电池工作的基础上，通过设计并合成全新的、功函数可调的交联共轭聚合物作为纳米晶太阳电池的空穴传输材料，调控载流子在界面的收集效率，同时在活性层里引入Cu等掺杂元素，降低电池的串联电阻，经器件的全面优化设计，最终获得转换效率超过13%的高效纳米晶太阳电池器件，为其商业化应用奠定基础。

无机纳米晶太阳电池和传统的硅基、无机薄膜太阳电池相比，具有制备工艺简单、原材料使用少、可通过溶液加工方式低成本制作大面积器件的优势。本课题通过界面重构、器件设计、空穴传输层优化等，设计如ITO/ZnO/CdS/CdSe/CdTe/HTL/Au的器件结构，抛弃传统单一的电子传输层，这将大大优化能级结构，减少能量损失，同时由于界面层的优化设计，形成偶极层，增强了内建电场，有利于载流子的收集和分离，通过器件设计的优化，从而全面利用太阳光谱；对这种无机纳米晶太阳电池器件材料选择、制备工艺以及界面修饰进行深入的研究。同时我们也将探索卷对卷打印技术在高效大面积无机纳米晶光伏器件中的应用。