A Dopant‐Free Polymeric Hole‐Transporting Material Enabled High Fill Factor Over 81% for Highly Efficient Perovskite Solar Cells

Abstract

Although perovskite solar cells (PVSCs) have achieved rapid progress in the past few years, most of the high‐performance device results are based on the doped small molecule hole‐transporting material (HTM), spiro‐OMeTAD, which affects their long‐term stability. In addition, some defects from under‐coordinated Pb atoms on the surface of perovskite films can also result in nonradiative recombination to affect device performance. To alleviate these problems, a dopant‐free HTM based on a donor‐acceptor polymer, PBT1‐C, synthesized from the copolymerization between the benzodithiophene and 1,3‐bis(4‐(2‐ethylhexyl)thiophen‐2‐yl)‐5,7‐bis(2‐alkyl)benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione units is introduced. PBT1‐C not only possesses excellent hole mobility, but is also able to passivate the surface traps of the perovskite films. The derived PVSC shows a high power conversion efficiency of 19.06% with a very high fill factor of 81.22%, which is the highest reported for dopant‐free polymeric HTMs. The results from photoluminescence and trap density of states measurements validate that PBT1‐C can effectively passivate both surface and grain boundary traps of the perovskite.

D–π–A‐Type Triazatruxene‐Based Dopant‐Free Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells

“…In addition, for CI‐B3 (Figure 3c), two strong and dispersive diffractions were observed at 0.3 and 0.4 Å −1 out‐of‐plane, which is probably due to the well‐aligned molecule stacking phase. [ 36,37 ] The CI‐B3 molecules are thus packed in favor of an edge‐on stacking fashion with well‐order, as schematically shown at Figure 3g.…”

High-efficiency perovskite solar cells with poly(vinylpyrrolidone)-doped SnO2as an electron transport layer

“…33,34 To further increase the PCE of PSCs, improvement of the opencircuit voltage (V OC ) and fill factor (FF) could be more feasible than increasing the short-circuit current (J SC ) because J SC is almost close to its limit (B26 mA cm À2 ) for perovskite solar cells with a bandgap of around 1.55 eV. 35 With these factors in mind, research efforts should begin with finding ways to increase V OC . To avoid charge accumulation at the ETL/perovskite interface, researchers developed several strategies to further increase the electron mobility of SnO 2 , which facilitates electron extraction.…”

Dopant‐Free Crossconjugated Hole‐Transporting Polymers for Highly Efficient Perovskite Solar Cells

“…The synthetic route for preparing PPEs is shown in Scheme 1, which is quite straightforward comparing with those reported for donor-acceptor type polymer HTMs. [59][60][61][62][63][64][65][66] The synthetic details and characterization data are provided in Supporting Information. Compound 1 was synthesized from the reaction of two commercial raw materials according to our previous work, [67] which can then be easily transferred to compound 2 via a www.advancedsciencenews.com www.advancedscience.com Corey−Fuchs reaction at a good yield of 71%.…”