Device Physics of the Carrier Transporting Layer in Planar Perovskite Solar Cells

Abstract

strategies for efficiency improvement. [3,4] Currently, it is found that the film quality of the perovskites synthesized by the newly developed approaches is capable of producing an absorption layer delivering the PCE of over 20%. The engineering of the interfacial properties has become a critical issue for the material scientists, engineers, and physicists. The further improvement of PCE requires multidisciplinary collaborative investigations. There are recent reports on the modifications of the commonly used carrier transport materials including the organic materials, inorganic materials, nanocomposites, etc. For the organic materials, 2,2′,7,7′-tetrakis(N,Nd i -p -m e t h o x y p h e n y l -a m i n e ) 9 , 9 ′spirobifluorene (Spiro-OMeTAD), poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and poly (triarylamine) (PTAA) are typically used to transport holes. [5][6][7][8][9][10][11][12][13][14][15][16][17] The fullerene based materials and their derivatives are also intensively studied as electron transport materials, such as the phenyl-C 61 -butyric acid methyl ester (PCBM), C 60 bathocuprione (BCP), etc. Meanwhile, the relatively low-cost nonfullerenes, e.g., 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′] dithiophene) (ITIC) and their derivatives that possess excellent optical and electrical properties compared with their fullerene counterparts are also promising for highly efficient and stable PVSCs. [18][19][20][21][22][23][24][25][26][27][28][29] Regarding the inorganic semiconductor materials, metal oxides possess superior stability and tunable optical and electrical properties compared with the organic semiconductor materials. The various metal oxides such as titanium dioxide (TiO 2 ), [13,[30][31][32][33][34][35][36][37][38] zinc oxide (ZnO), [39,40,38,19,41] and tin oxide (SnO 2 ) [42][43][44][45][46][47][48][49] are commonly used as the electron transport layer (ETL), while nickel oxide (NiO x ), [50][51][52][53] copper oxide (Cu 2 O), [54,55] copper (I) thiocyanate (CuSCN), [16,56,57] copper gallium oxide (CuGaO 2 ), [58] and nickel cobalt oxide (NiCoO x ) [12,59] serve as the hole transport layer (HTL) in the PVSCs. [60,61] Meanwhile, several theoretical studies based on different approaches to the device models have also been reported, focusing on the underlying physics of the efficiency loss, [62] hysteresis phenomena, [63][64][65][66] etc., which are substantially affected by the carrier transport layer (CTL) properties. These models enable the analysis of the device performance from the macroscopic circuit aspect [67] to the microscopic carrier level, [65] which offer a comprehensive understanding of the device physics of CTLs in PVSCs.Perovskite solar cells (PVSCs) have emerged as a promising candidate for addressing the energy crisis due to their rapid efficiency improvement up to 24.2% within 10 years. The defects existing in perovskite film have been found to be as low as 10 15 cm ...

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

“…On the device level, the light-harvesting efficiency can also be affected by the optical properties of these layers, especially those facing sunward (e.g., ESL in the n-i-p configuration). Table 1 gives a summarized comparison of SnO 2 with state-of-the-art ESLs, [34,46,[55][56][57][58] which we discuss next in greater detail, with a focus on the n-i-p configuration.…”

Low-Temperature Growing Anatase TiO2/SnO2 Multi-dimensional Heterojunctions at MXene Conductive Network for High-Efficient Perovskite Solar Cells

“…On the basis of a low-temperature anneal at 75 °C, the TiCl 4 solution can be translated into needle-like TiO 2 layer in rutile phase when it is heated by covering a soft film, yet the PSC based on this TiO 2 ETL just shows a PCE of 17.09% [22]. In a low-temperature anneal at 120 °C, a TiO 2 layer can be also formed based on aqueous TiCl 4 . Although the resultant TiO 2 /SnO 2 composite can contribute a maximum PCE of 21.27% [23], this PCE is still restricted by the amorphous phase of TiO 2 here [17].…”

“…In a conventional upright structure in PSCs, the light absorption property of perovskite layer can be affected by the optical transmittance property of ETL by reducing optical energy loss [ 3 ]. The charge carriers in device can be regulated by the semiconductive energy-level property of ETL, through selectively transporting electrons and blocking holes from the adjacent perovskite layer [ 4 ]. Further, the amount of photon-excited carrier in perovskite layer can be restricted by the ETL, because the crystal size of perovskite can be affected by the hydrophobicity of the below ETL in preparation [ 5 , 6 ].…”

1D‐2D Synergistic MXene‐Nanotubes Hybrids for Efficient Perovskite Solar Cells

“…[ 6 ] However, SnO 2 suffers from oxygen vacancy‐related defects resulting in non‐radiative trap‐assisted recombination, ionic charge accumulation at the SnO 2 /perovskite interface, and hysteresis thus deteriorating the PV performance and affecting the reliability and reproducibility of the devices. [ 7–9 ]…”