Efficient And Stable Multi-Blend Inverted Perovskite Solar Cells Were Prepared By Surface Interface Modification

Poly(bis（4-phenyl）（2,4,6-trimethylphenylamine）（PTAA）-based inverted perovskite solar cells（PSCs）are one of the most efficient kind of the inverted PSCs reported to date.However,the hydrophobicity of PTAA leads to wettability mismatch issue,which seriously impact on the device repeatability and result serious interface recombination loss.In addition,the energy loss at the interface of perovskite/phenyl-C₆₁methyl butyrate（PCBM）greatly limits the energy conversion efficiency（PCE）and stability of inverted PSCs.Thus,many researches of interface engineering to improving the PCE and stability of inverted PSCs have been carried out gradually,which will have important significance for promoting the commercialization of PSCs.In this paper,the interface of PTAA/perovskite and perovskite/PCBM are modified and improved through multiple interface modification strategies,so as to prepare inverted PSCs with high repeatability,efficiency and stability.The main research contents of this paper are as follows:1)A collaborative interface modification strategy based on polyvinyl oxide（PEO）and tetrapropyl ammonium bromide（TPAB）are introduced to improve the device performance and repeatability.The improvement of perovskite film,interface contacting and device performance by this modification strategy is systematically studied.The results show that PEO can significantly improve the wetting of perovskite precursor solution on the surface of PTAA,and correspondingly improve the perovskite film forming quality,reduce the defects of the perovskite film as well as enhance the contact of anode interface of the device.The proportion of short-circuit devices are decreased from 44.23%to 0%,and the average PCE increased from 8.4%to 18.93%.However,the humidity stability of devices is poor.In order to deal with the problem of cathode interface and the insufficient humidity stability of the device,TPAB surface treatment strategy is furtherly introduced to passivate the cathode interface defect and construct the cathode interface electric field,thus improving the cathode interface charge extraction and transmission.At the same time,the introduction of TPAB improves the hydrophobic property of perovskite films.The maximum PCE of the device can reach up to 21.62%.Meanwhile,the average PCE of the devices can maintain 80%,96%of the initial value after 298 hours in air（23℃@RH=25±5%）and after 217 days in N₂（23℃）,respectively.2)An efficient interface modification strategy based on cinnamyl alcohol（CA）is proposed to improve the interface contact and device performance.The effect of CA interface modification on physicochemical properties of perovskite films and device performance are studied in detail.The results show that the wettability of polar perovskite precursor solution on the surface of PTAA film is obviously improved after interface modification treatment of CA.The quality of perovskite film and the anode interface of PTAA/perovskite are obviously improved.The internal defects of perovskite film and interface energy loss are obviously reduced.The short circuit and abnormal phenomenon of the device are eliminated.The device performance and repeatability are significantly improved.The average PCE of the device is increased from 10.22%to 19.41%by CA modification,and the PCE of the best device is also increased from 18.33%to 21.31%.In addition,the stability of the device is also greatly improved under various conditions.The average PCE of the device can maintain 70%of the initial value after 437 hours in air（23℃@RH=25±5%）,while the standard device only maintains 45%of the initial PCE.Under thermal press（85℃）,the average PCE of CA devices can maintain 73%of the initial value after 148 h,while the average PCE of standard devices can only maintain 36%.