Investigation on a dopant-free hole transport material for perovskite solar cells†
A tetraphenylethene derivative (TPE-4DPA) was synthesized and applied as the hole transporting material for planar perovskite solar cells. The use of TPE-4DPA for device fabrication requires no oxidization process and lower amount of additives, delivering an overall power conversion efficiency of 12.81%. Remarkably, even in the absence of the additives, the solar cell based on the pristine TPE-4DPA still generates a Jsc as high as 20.50 mA cm−2, and moderate PCE of 9.12%. Using no additives is of critical importance, which simultaneously increases the stability of the devices and reduces the fabrication cost of perovskite solar cells, when compared to devices using Li-TFSI doped Spiro-OMeTAD.