Rasal Akash S, Dehvari Khalilalrahman, Getachew Girum, Korupalli Chiranjeevi, Ghule Anil V, Chang Jia-Yaw
Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan, Republic of China.
Nanoscale. 2021 Mar 21;13(11):5730-5743. doi: 10.1039/d0nr07963d. Epub 2021 Mar 16.
For quantum dot sensitized solar cells (QDSSCs), modifying conservative polysulfide electrolytes with polymer additives has been proven as an effective method to control charge recombination processes at the TiO/QDs/electrolyte interface and to accomplish efficient cell devices. In this respect, the polysulfide electrolyte is modified with polymeric and sulfur-rich graphitic carbon nitride (SGCN) to enhance the photovoltaic performance of QDSSCs. For the first time, SGCN is used to passivate surface trap states and act as the steric hindrance between TiO/QDs/electrolyte interfaces. The QDSSCs fabricated with GCN and SGCN additives exhibited higher efficiencies, especially improved short-circuit current (J) and fill factors (FFs) than those of the liquid electrolyte. Cu-In-S sensitized QDSSCs constructed with GCN and SGCN additives exhibited efficiencies of 6.73% and 7.13%, respectively, whereas the liquid electrolytes delivered an efficiency of 6.16%. Additionally, the applicability of SGCN additives in various Cu-based QDSSCs to enhance their photovoltaic performance is further verified using Cu-In-Se QDSSCs. An increase in the conversion efficiencies of QDSSCs with SGCN additives is possibly due to (1) their electron-rich surface which can act as an obstacle for electron-hole recombination, thereby suppressing the back-transfer of photo-induced electrons to the QD/electrolyte interface; (2) SGCN facilitates the reduction of S to S redox couple, thus providing holes towards the QDs/electrolyte more efficiently. Overall, this work provides an innovative and economic additive to modify polysulfide electrolytes, thereby controlling the TiO/QDs/electrolyte interfaces of QDSSCs.
对于量子点敏化太阳能电池（QDSSCs），用聚合物添加剂修饰传统的多硫化物电解质已被证明是一种控制TiO/QDs/电解质界面电荷复合过程并实现高效电池器件的有效方法。在这方面，用聚合物和富含硫的石墨相氮化碳（SGCN）对多硫化物电解质进行修饰，以提高QDSSCs的光伏性能。首次使用SGCN来钝化表面陷阱态，并在TiO/QDs/电解质界面之间起到空间位阻作用。用GCN和SGCN添加剂制备的QDSSCs表现出更高的效率，特别是与液体电解质相比，短路电流（J）和填充因子（FFs）有所提高。用GCN和SGCN添加剂构建的Cu-In-S敏化QDSSCs的效率分别为6.73%和7.13%，而液体电解质的效率为6.16%。此外，使用Cu-In-Se QDSSCs进一步验证了SGCN添加剂在各种铜基QDSSCs中增强其光伏性能的适用性。添加SGCN添加剂的QDSSCs转换效率的提高可能是由于：（1）其富电子表面可作为电子-空穴复合的障碍，从而抑制光生电子向QD/电解质界面的反向转移；（2）SGCN促进S到S氧化还原对的还原，从而更有效地向QDs/电解质提供空穴。总体而言，这项工作提供了一种创新且经济的添加剂来修饰多硫化物电解质，从而控制QDSSCs的TiO/QDs/电解质界面。
