Amorphous Hole‐Transporting Material based on 2,2′‐Bis‐substituted 1,1′‐Biphenyl Scaffold for Application in Perovskite Solar Cells

Abstract

Perovskite solar cells are considered a promising technology for solar-energy conversion, with power conversion efficiencies currently exceeding 20 %. In most of the reported devices, Spiro-OMeTAD is used for positive-charge extraction and transport layer. Although a number of alternative hole-transporting materials with different aromatic or heteroaromatic fragments have already been synthesized, a cheap and well-performing hole-transporting material is still in high demand. In this work, a two-step synthesis of a carbazole-based hole-transporting material is presented. Synthesized compounds exhibited amorphous nature, good solubility and thermal stability. The perovskite solar cells employing the newly synthesized material generated a power conversion efficiency of 16.5 % which is slightly lower than that obtained with Spiro-OMeTAD (17.5 %). The low-cost synthesis and high performance makes our hole-transport material promising for applications in perovskite-based optoelectronic devices.

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]<...>…”

Nonspiro, Fluorene‐Based, Amorphous Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells

“…The optimized champion device efficiency for V1050, V1061, SpiroOMeTAD, and corresponding photo voltaic performance parameters are shown in Figure 6. The Spiro-OMeTAD [26] 126 449 5. Thermal decomposition temperature was registered at 5% weight loss; c)…”

“…[17][18][19][20][21][22][23][24] Recently, we have presented the synthesis of a new class of efficient HTMs. [25,26] Their structure consists of two 4,4′dimethoxydiphenylamine 3,6disubstituted carbazole frag ments linked by a nonplanar unit. Synthesis of these HTMs was performed by a simple twostep synthetic procedure pro viding a target product in high yield.…”

Inexpensive Hole‐Transporting Materials Derived from Tröger's Base Afford Efficient and Stable Perovskite Solar Cells

“…Successful examples include branched methoxydiphenylamine-substituted fluorine [15] and bifluorenylidene-based derivatives, [16] spiro[fluorene-9,9'-xanthene]-based materials, [17][18][19] and methoxydiphenylamine-substituted branched carbazole derivatives. [20][21][22] Nevertheless,these molecules [15,18] are synthesized by cross-coupling reactions that require transition-metal catalysts,i nert reaction conditions,a nd extensive product purification to remove catalyst residue, which in turn increases cost of the final product.…”