Dopant‐Free, Donor–Acceptor‐Type Polymeric Hole‐Transporting Materials for the Perovskite Solar Cells with Power Conversion Efficiencies over 20%

Abstract

The rich molecular design of electron donor (D)–acceptor (A) polymers offers many valuable clues to obtain high‐efficiency hole‐transporting materials (HTMs) for use in perovskite solar cells (PVSCs). The fused aromatic or heteroaromatic units can increase the conjugation of the polymer backbone to facilitate electron delocalization, which increases the rigidity of adjacent units to prevent rotational disorder and lower the reorganization energy, leading to improved carrier mobility and optimized film morphology. In this work, fused‐ring ladder‐type indacenodithiophene and indacenodithieno[3,2‐b]thiophene are used as D units, benzodithiophene‐4,8‐dione as the A unit, and thienothiophene as a π‐bridge to form the D–A polymers PBDTT and PBTTT, respectively. Both polymers exhibit favorable properties as HTMs including suitable energy levels, high hole mobility, and excellent film quality. Both dopant‐free HTMs endow n‐i‐p PVSCs with promising performance and stability. A maximum power conversion efficiency of 20.28% is achieved for PBDTT‐based devices, which is among the highest values reported to date.

A dopant-free hole transport material boosting the performance of inverted methylamine-free perovskite solar cells

“…1c and d, the main chain structure of PFDTS exhibits better planarity than PTAA, benefiting π–π stacking of the solid phase. 33 Fig. 1e and f show the electrostatic potential surface distribution of PTAA and PFDTS, respectively.…”

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%.…”

Combination of Metal Oxide and Polytriarylamine: A Design Principle to Improve the Stability of Perovskite Solar Cells

“…In brief, it was demonstrated that the SiO x thin layer and reduced MO x layers appeared between Si and MO x , leading to Fermi level equilibration across the interface [14]. In addition, such advantages of MO x , with high conductivity and the ability to form a smooth pinholefree layer with organic HTLs, enable high efficiencies in PSCs of more than 20% [15,16]. Additionally, the high transparency of MO x permits their application in inverted PSC configurations [17].…”