Molecular structure simplification of the most common hole transport materials in perovskite solar cells

Abstract

A spiro-type hole transport material with simplified molecular structure has been synthesized and used in efficient perovskite solar cells.

Low‐Cost Carbazole‐Based Hole‐Transport Material for Highly Efficient Perovskite Solar Cells

“…The UV/Vis absorption spectra of Cz-OMeTAD and Spiro-OMeTAD in CH 2 Cl 2 are showni n Figure 3a.S imilart ot hat reported previously, [35] Spiro-OMeTAD exhibits characteristica bsorption peaks at 310 and 390 nm, which were attributed to the aromatic ring and the conjugated triarylamine system,r espectively.C ompared to Spiro-OMeTAD, Cz-OMeTAD exhibited one more absorption peak at 420 nm;t his weaker characteristic peak may be ascribed to the ethyl substituent of the carbazole moiety.T he corresponding Ta uc plots of the absorption spectra are depicted in Figure 3b,f rom which the optical band gap (E g )c an be evaluated by extending the linear portion of the plot to the bindingenergy axis. The decomposition temperature corresponding to a5%w eight loss (T d )i sa pproximately 423 8C To evaluatet he potentialo fC z-OMeTAD for application in photovoltaic devices, we conducted as eries of measurements to characterize its photoelectrical properties, with the commonly used Spiro-OMeTAD used as ar eference.…”

“…The decomposition temperature corresponding to a5%w eight loss (T d )i sa pproximately 423 8C (Figure 2a To evaluatet he potentialo fC z-OMeTAD for application in photovoltaic devices, we conducted as eries of measurements to characterize its photoelectrical properties, with the commonly used Spiro-OMeTAD used as ar eference. The UV/Vis absorption spectra of Cz-OMeTAD and Spiro-OMeTAD in CH 2 Cl 2 are showni n Figure 3a.S imilart ot hat reported previously, [35] Spiro-OMeTAD exhibits characteristica bsorption peaks at 310 and 390 nm, which were attributed to the aromatic ring and the conjugated triarylamine system,r espectively.C ompared to Spiro-OMeTAD, Cz-OMeTAD exhibited one more absorption peak at 420 nm;t his weaker characteristic peak may be as- Spiro-OMeTAD and 2.75 eV for Cz-OMeTAD ( Figure 3b). For HTMs used in photovoltaic devices,s uitable energy levels can facilitate the transport of photoexcited holes from the light-absorber layer to the anode.H ere, we conducted CV characterization to determine the energy of the HOMO of Cz-OMeTAD, with the ferrocene/ferrocenium couple being used as an internal reference.…”

Recent Advances in Spiro‐MeOTAD Hole Transport Material and Its Applications in Organic–Inorganic Halide Perovskite Solar Cells

“…The motivation of cost reduction led Shi et al to fabricate a simplified new HTM based on spiro‐MeOTAD. The simplified HTM contains only two dimethoxy‐diphynelamine units, and the other two were simply replaced by two tert ‐butyl units.…”

“…The thermal stability was barely affected, but the hole mobility was enhanced. The new HTM was also investigated in PSCs and provided similar PCEs to those of spiro‐MeOTAD reference with a champion of 16.6% as compared to 16.1% for the reference . Similarly, Li et al replaced two of the dimethoxy‐diphynelamine units by acridine‐fluorene incorporated as part of the spiro core with different modifications to achieve suitable HTMs.…”

A facilely synthesized ‘spiro’ hole-transporting material based on spiro[3.3]heptane-2,6-dispirofluorene for efficient planar perovskite solar cells

“…11 Therefore, it is highly desirable to develop low cost, and more straightforward routes of synthesis to render highly efficient small-molecule HTMs as alternatives to spiro-OMeTAD in solar cell application. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] In this respect, many kinds of molecular HTMs afforded by facile synthetic steps from commercially available raw materials were recently developed and tested in PSCs, e.g., methoxydiphenylamine-substituted carbazole, 11,12 diuorobenzene, 13 biphenyl, 12 pyrene, 14 spiro-based derivatives, [15][16][17][18][19][20] tetraphenylethenederivative, 21 dioxythiophene, 22,23 and triphenylamine. 29 Specically, a simple diuorobenzene-core arylamine hole conductor (DFTAB) via only one synthetic step from inexpensive starting materials was designed as HTM for PSCs and a stabilized PCE of 10.4% was obtained.…”