Study Of P3CT-K Based Hole Transporting Materials In Inverted Mapb I3 Perovskite Solar Cells

The power conversion efficiency（PCE）of organic-inorganic hybrid perovskite solar cells（PSCs）based on lead halide perovskites has risen from an initial 3.8%to the recent 25.2%within the past decade.Organic-inorganic hybrid perovskites have intrigued great interests as a promising candidate of the third generation solar cells,due to their tunable composition with appealing properties,such as large absorption coefficient,small exciton binding energy,long carrier diffusion length,etc.Their widely used device structures can be categorized as mesoporous structure,conventional planar heterostructure and inverted planar heterostructure.Among them,inverted planar heterostructure has drawn particular attention from researchers because of its solution route and simple preparation.Herein,this paper is aimed at addressing the problem of hole extraction and transportation in inverted PSCs,and propose corresponding solutions.（1）Conjugated polyelectrolyte cavity transport material has the disadvantage of low hole transpotation and easy aggregation.In order to solve this problem,we carry on the research and analysis and propose the solution of small molecule modification.By introducing trifluorobenzene borane（TPB）to modify P3CT-K simply,the aggregation of P3CT-K thin films has been effectively improved,and the hole migration capability of the films is also improved.P3CT-K（TPB）can effectively extract and transmit photo-generated cavitation,which is beneficial to the crystallization of perovskite（MAPb I₃）in order to obtain larger grain size,reduction of non-radiation compound and improvement of carrier life.As a result,the final device short-circuit current and open circuit voltage were improved significantly,and the photoelectric conversion efficiency of the device was up to 20.7%.（2）Nickel oxide is also a widely used inorganic hole transport material for inverted PSCs.The problems of lattice mismatch and unsatisfactory hole extraction capability at interface between nickel oxide and perovskite have been analyzed and studied,in which the solution of conjugate electrolyte modification has been proposed.P3CT-K（TPB）is introduced as surface modification material to solve the contact problem between nickel oxide and perovskite.The resultant device achieves a high PCE of over 20%,showing a 28%enhancement compared to the control device.