Indolocarbazole based small molecules: an efficient hole transporting material for perovskite solar cells

Abstract

To date, Spiro-OMeTAD, which is an expensive organic compound, is used as the benchmark hole transporting materials (HTMs) in perovskite based solid state solar cells. Development of an inexpensive HTM and competitive performance to Spiro-OMeTAD is therefore significantly important for commercialization of perovskite cells. Herein, an indolocarbazole based small molecule derivative (C12-Carbazole) has been introduced as environmentally stable, cost effective and highly efficient HTM. In contrast to the power conversion efficiency of 9.62 % exhibited by the Spiro-OMeTAD based solid state solar cell, the C12-Carbazole based device under the same experimental conditions has demonstrated an enhanced power conversion efficiency of 11.26 %.The improved photovoltaic performance of the C12-Carbazole based device is attributed to the lowering of carrier recombination by better hole extraction ability of the C12-Carbazole, which has demonstrated remarkably higher hole mobility compared to Spiro-OMeTAD.

Facilely Synthesized spiro[fluorene‐9,9′‐phenanthren‐10′‐one] in Donor–Acceptor–Donor Hole‐Transporting Materials for Perovskite Solar Cells

“…Recently,o rganic-inorganic halide perovskite solar cells (PSCs) have attracted considerable attention because of their outstanding performance in converting sunlight to electricity at al ow cost compared with silicon-based photovoltaict echnology.T he first PSCs, as ana-lyzed by Miyasaka in 2009, had power conversion efficiency (PCE) of 3.8 %. [12][13][14] To overcome these issues, numerouss tudies have focusedo nl ow-costp roduction without as piro-based linkage in the HTM, mainly using acene, [15] carbazole, [16][17][18][19][20][21][22][23] indole, [24][25][26] phenothiazine, [27] phenoxazine, [28] thiophene, [29][30][31][32][33][34][35] triarylamine, [36][37][38][39] triazateuxene, [40][41][42][43] and truxene. [11] In the conventional devicec onfiguration, 2,2',7,7'-tetrakis[N,N-di(4methoxyphenyl)amino]-9,9'-spirobifluorene( Spiro-OMeTAD) is generally used as the hole-transporting material( HTM) and has demonstrated PCEs of 20-21 %i nP SCs.…”

“…The spiro-based structure of this HTM also ensures superiors tability,h igher T g ,a nd favorable film morphology.H owever,S piro-OMeTAD is very expensive ( % 261 $g À1 ); synthesis of the material requires af ive-step procedure with at otal yield of less than 30 %. [12][13][14] To overcome these issues, numerouss tudies have focusedo nl ow-costp roduction without as piro-based linkage in the HTM, mainly using acene, [15] carbazole, [16][17][18][19][20][21][22][23] indole, [24][25][26] phenothiazine, [27] phenoxazine, [28] thiophene, [29][30][31][32][33][34][35] triarylamine, [36][37][38][39] triazateuxene, [40][41][42][43] and truxene. [44,45] Considerable efforts have also been devoted to investigating suitable HTMs by replacing the spiro-based core with novel spiro-based HTMs like spiro-acridine-fluorene, [46,47] spiro-bi[thieno [3,4-b] [1,4]dioxepine], [48] dispiro-oxepine, [49] spiro[fluorene-9,9'-xanthene], [6,[50][51]<...>…”

Design of Cone‐Shaped Hole Transporting Material Organic Structures for Perovskite Solar Cells Applications

“…Hence the probability of the visible light induced excitation would be lower in HTMs. Smaller molecular size of H1 and H2 compared to S‐OMeTAD permits better pore filling, which is beneficial to enhance the hole‐extracting efficiency of PSC . Compared to the solution state, HTM spin coated on glass exhibits broad and slightly red shifted absorption ( Figure ).…”

π-Conjugated Materials as the Hole-Transporting Layer in Perovskite Solar Cells

“…A perovskite solar cell based on a direct architecture using the CH 3 NH 3 PbI 3 perovskite (synthesized using a two-step sequential deposition procedure) has shown a short-circuit current density of 21.13 mA¨cm´2 and an open circuit tension of 860 mV, resulting in a power conversion efficiency of 11.26% for a fill factor of 62% [27]. Such relevant results remain to be more systematically reproduced, considering that the corresponding reference cell based on Spiro-OMeTAD was associated with a PCE of 9.62% only and a very low FF of 47%.…”