Recent Advances in Organic Hole Transporting Materials for Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) with advantages of exceptional photovoltaic performance and facile solution‐processed fabrication have shown great potential in future scalable application. After about a decade of rapid development, this new PSCs technology demonstrates over 25% efficiency, a comparable performance with traditional silicon solar cells. Further, the development of PSCs in the direction of scalable production still highly relies on designing innovative materials with low cost and high efficiency. Recently, a great number of functional organic molecules as hole transport materials (HTMs) have been designed, synthesized, and studied in PSCs, including molecules with planar structure, 3D geometry, or different core units. Discovering the correlation between their chemical structures and physicochemical properties plays a fundamental role in supervising future molecular design and synthesis. Herein, recent advances in organic molecular HTMs with various structures in typical and reverse PSCs device configuration are summarized, including doped and doping‐free materials. By evaluating the structural modification and analyzing their effects on photovoltaic performance, the goal is to generate universal strategies for preparing low‐cost and efficient HTMs, paving the way for future scalable application of PSCs.

Advancements in organic small molecule hole-transporting materials for perovskite solar cells: past and future

“…4. 25,27,[55][56][57][58][59][60] (1) Generate highly stable radical cations quantitatively and reproducibly at a reasonable rate in order to improve charge-transport efficiency (2) give off desirable properties, such as inertness, in the event that byproducts are inevitable (i.e., increased hydrophobicity or thermal stability, reduced phase segregation). (3) The PSC (i.e., adequate energetic alignment of HTL with PAL for hole extraction) is highly efficient and stable, (4) but sustaining minimal prices (i.e.…”

Face-on oriented hydrophobic conjugated polymers as dopant-free hole-transport materials for efficient and stable perovskite solar cells with a fill factor approaching 85%

“…Compared with inorganic HTMs 28–40 and organic molecular HTMs, 25,41–43 HTMs based on conjugated polymers possess high solution operability due to the inherent high carrier mobility, excellent film-forming properties, and sufficient hydrophobicity. 44–47 Currently, several dopant-free polymer HTMs have been employed in PSCs to realize high PCEs and excellent device stability, such as pBBTa-BDT2, 48 RCP, 23 asy-PBTBDT, 49 PCDTBT1, 50 (alkoxy-)PTEG, 51,52 PC3, 45 P3HT 53,54 and many others.…”

Starburst Carbazole Derivatives as Efficient Hole Transporting Materials for Perovskite Solar Cells

“…Up to now, various types of HTMs have been developed and some of them have been reported to show comparable performance in comparison with that of spiro-OMeTAD; however, most of them still require multistep synthetic procedures. [12,[18][19][20][21][22][23][24][25] Carbazole (Cbz) moiety has been widely used as a building block in HTMs for PSCs due to its low cost, good charge transporting ability, chemical stability, and facile modification with a wide variety of functional groups. [26][27][28][29][30][31][32][33][34][35][36][37][38][39] In addition, the carbazole-based HTMs have the advantage in that they do not contain methoxy substituents, such as those found on spiro-OMeTAD, and could increase the hydrophilicity of the HTM layer, thus affecting the device stability.…”