Hole transport layer (HTL) is very important for the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). As current state‐of‐the‐art HTL, Li‐TFSI doped spiro‐OMeTAD often suffers low conductivity and the hydrolysis of the additive Li‐TFSI, which significantly hinders the further improvement of PCE of PSCs. Besides, conventional spiro‐OMeTAD has no functional of directly passivating the perovskite crystal defects. Herein, multifunctional TiO2nanoparticles (NPs)‐modified CNT (CNT:TiO2) doped spiro‐OMeTAD (spiro‐OMeTAD+CNT:TiO2) HTL is reported for the first time. The incorporated CNT:TiO2not only significantly increases the conductivity of spiro‐OMeTAD+CNT:TiO2, but also effectively passivates the crystal defects of perovskite layer. The optimized PSCs with spiro‐OMeTAD+CNT:TiO2HTL achieved a peak PCE of 21.53%, much higher than that (17.90%) of the conventional spiro‐OMeTAD based PSCs and also show significantly improved stability.
The hole transport layer (HTL) is one of the key components in planar perovskite solar cells. This study reports a new kind of HTL fabricated using atomic layer deposition (ALD). By alloying TiO2with IrO
- NSF-PAR ID:
- 10063562
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 5
- Issue:
- 16
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Organic–inorganic hybrid perovskite solar cells (PVSCs) have become the front‐running photovoltaic technology nowadays and are expected to profoundly impact society in the near future. However, their practical applications are currently hampered by the challenges of realizing high performance and long‐term stability simultaneously. Herein, the development of inverted PVSCs is reported based on low temperature solution‐processed CuCrO2nanocrystals as a hole‐transporting layer (HTL), to replace the extensively studied NiO
x counterpart due to its suitable electronic structure and charge carrier transporting properties. A ≈45 nm thick compact CuCrO2layer is incorporated into an inverted planar configuration of indium tin oxides (ITO)/c‐CuCrO2/perovskite/[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM)/bathocuproine (BCP)/Ag, to result in the high steady‐state power conversion efficiency of 19.0% versus 17.1% for the typical low temperature solution‐processed NiOx ‐based devices. More importantly, the optimized CuCrO2‐based device exhibits a much enhanced photostability than the reference device due to the greater UV light‐harvesting of the CuCrO2layer, which can efficiently prevent the perovskite film from intense UV light exposure to avoid associated degradation. The results demonstrate the promising potential of CuCrO2nanocrystals as an efficient HTL for realizing high‐performance and photostable inverted PVSCs. -
Abstract Two key interfaces in flexible perovskite solar cells (f‐PSCs) are mechanically reinforced simultaneously: one between the electron‐transport layer (ETL) and the 3D metal‐halide perovskite (MHP) thin film using self‐assembled monolayer (SAM), and the other between the 3D‐MHP thin film and the hole‐transport layer (HTL) using an in situ grown low‐dimensional (LD) MHP capping layer. The interfacial mechanical properties are measured and modeled. This rational interface engineering results in the enhancement of not only the mechanical properties of both interfaces but also their optoelectronic properties holistically. As a result, the new class of dual‐interface‐reinforced f‐PSCs has an unprecedented combination of the following three important performance parameters: high power‐conversion efficiency (PCE) of 21.03% (with reduced hysteresis), improved operational stability of 1000 h
T 90(duration at 90% initial PCE retained), and enhanced mechanical reliability of 10 000 cyclesn 88(number of bending cycles at 88% initial PCE retained). The scientific underpinnings of these synergistic enhancements are elucidated. -
Abstract The ability to passivate defects and modulate the interface energy‐level alignment (IEA) is key to boost the performance of perovskite solar cells (PSCs). Herein, we report a robust route that simultaneously allows defect passivation and reduced energy difference between perovskite and hole transport layer (HTL) via the judicious placement of polar chlorine‐terminated silane molecules at the interface. Density functional theory (DFT) points to effective passivation of the halide vacancies on perovskite surface by the silane chlorine atoms. An integrated experimental and DFT study demonstrates that the dipole layer formed by the silane molecules decreases the perovskite work function, imparting an Ohmic character to the perovskite/HTL contact. The corresponding PSCs manifest a nearly 20 % increase in power conversion efficiency over pristine devices and a markedly enhanced device stability. As such, the use of polar molecules to passivate defects and tailor the IEA in PSCs presents a promising platform to advance the performance of PSCs.
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Abstract The ability to passivate defects and modulate the interface energy‐level alignment (IEA) is key to boost the performance of perovskite solar cells (PSCs). Herein, we report a robust route that simultaneously allows defect passivation and reduced energy difference between perovskite and hole transport layer (HTL) via the judicious placement of polar chlorine‐terminated silane molecules at the interface. Density functional theory (DFT) points to effective passivation of the halide vacancies on perovskite surface by the silane chlorine atoms. An integrated experimental and DFT study demonstrates that the dipole layer formed by the silane molecules decreases the perovskite work function, imparting an Ohmic character to the perovskite/HTL contact. The corresponding PSCs manifest a nearly 20 % increase in power conversion efficiency over pristine devices and a markedly enhanced device stability. As such, the use of polar molecules to passivate defects and tailor the IEA in PSCs presents a promising platform to advance the performance of PSCs.