Efficient and Stable Inverted Planar Perovskite Solar Cells Using a Triphenylamine Hole‐Transporting Material

Abstract

Inverted perovskite solar cells (PSCs) with a p-i-n structure have attracted great attention. Normally, inorganic p-type metal oxides or polymers are used as the hole-transport material (HTM), a vital component in the inverted PSCs. However, this type of HTM often requires high processing temperatures and/or high costs. On the other hand, a commonly used organic HTM, poly(3,4-ethylenedioxythiophene polystyrene sulfonate (PEDOT:PSS), is sensitive to humidity and thus affects the stability of the PSCs. Herein, we employ a small molecule, 4,4',4''-tris(N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) to replace PEDOT:PSS as a new HTM for inverted PSCs. Compared to a PEDOT:PSS-based device, m-MTDATA-based PSCs exhibit enhanced performance. The highest power conversion efficiency (PCE) was notably improved from 13.44 % (PEDOT:PSS) to 18.12 % (m-MTDATA), suggesting that m-MTDATA could be an efficient HTM to achieve high performance inverted PSCs. Furthermore, the m-MTDATA-based device demonstrated improved stability (retaining 90 % PCE) under ambient conditions over 1000 h compared with the PEDOT:PSS-based devices (retaining 40 % PCE).

Grain Enlargement and Defect Passivation with Melamine Additives for High Efficiency and Stable CsPbBr3 Perovskite Solar Cells

“…The VB of M‐CsPbBr 3 is examined from UPS characterizations according to the formula E VB = hv −( E cutoff − E onset ), the conduction band can be calculated according to the E g obtained from UV/Vis absorption measurements (Figure S6). The VB of M‐CsPbBr 3 (−5.60, −5.58, −5.61, and −5.63 eV for 0.5 %, 1 %, 2 %, and 4 % M‐CsPbBr 3 , respectively) is shifted up to approach the work function of carbon compared with that of the pristine perovskite (−5.66 eV), indicating a reduced energy level difference between the perovskite layer and carbon electrode, which facilitates the transportation as well as extraction of holes and reduces the loss of energy and photogenerated electrons at the interface for improved PCE …”

“…The VB of M-CsPbBr 3 (À5.60, À5.58, À5.61, and À5.63 eV for 0.5 %, 1%,2%, and 4%M-CsPbBr 3 ,respectively) is shiftedu pt oa pproacht he work function of carbon compared with that of the pristine perovskite(À5.66 eV), indicating ar educed energy level difference between the perovskite layer and carbon electrode, which facilitates the transportation as well as extraction of holes and reducest he loss of energy and photogenerated electrons at the interfacef or improved PCE. [36][37][38] The photocurrent-voltage (J-V)c urveso fP SCs based on CsPbBr 3 with or without melamine are measured under simulated AM 1.5G (100 mW cm À2 )s olari llumination (Figure 4c). Ta ble 1s ummarizes the photovoltaic parameters of V OC ,s hortcircuit current density (J SC ), fill factor (FF), and PCE for various devices.T he photovoltaic performance of the devices based on M-CsPbBr 3 is evidently improved, ac hampion 1%M-CsPbBr 3 -based device displays the optimal performance with a PCE of 9.65 %, J SC of 7.42 mA cm À2 , V OC of 1.584 V, andF Fo f 82.11%,y ieldingamarked improvement in comparison with the pristine CsPbBr 3 PSC (PCE:6 .07 %, J SC :5 .87 mA cm À2 , V OC : 1.401 V, and FF:7 3.80 %) and other reportedC sPbBr 3 solar cells.…”

The balance between efficiency, stability and environmental impacts in perovskite solar cells: a review

“…The most common approach is substituting lead with tin, but using elements to form halide double perovskites (elpasolites) have also been explored [35]. Interestingly, a lead-free solar cell, based on a CsSnI 3 light absorber (as a CH 3 NH 3 PbI 3 replacement) was also reported, although PCE was very poor and only improved upon the addition of SnF 2 to the active layer (best for 20% addition), but on the other hand this showed good stability for more than 250 h, especially those replacing the spiro-OMeTAD by m-MTDATA as HTL [36], while in CH 3 NH 3 PbI 3 cells, this substitution lead to more than 1000 h stable cells [37]. More recently, the replacement of spiro-OMeTAD by a Zn-derivative porphirin in a lead-free solar cell has led to extended stability up to 60 h for water stability and 100 h for thermal stability, an increment of 75% when compared to control cells [38].…”

High‐Performance Inverted Planar Perovskite Solar Cells Enhanced by Thickness Tuning of New Dopant‐Free Hole Transporting Layer

“…good solubility for solution processing. So since Guo reported the first inverted planar PSCs, lots of efforts have conducted to develop suitable HTLs . But up to now, very few suitable HTMs are available for highly efficient and stable inverted planar PSCs .…”