Homogeneous doping of entire perovskite solar cells via alkali cation diffusion from the hole transport layer

2021 ◽  
Vol 9 (14) ◽  
pp. 9266-9271
Author(s):  
Mengjiong Chen ◽  
Hong Wei Qiao ◽  
Ziren Zhou ◽  
Bing Ge ◽  
Jingjing He ◽  
...  

Alkali metal ions spontaneously diffuse from the hole transport layer into perovskite layer and electron transport layer, which could enhance the conductivity of NiOx films and modulate perovskite layer electronic states, simultaneously.


2021 ◽  
Vol 21 (7) ◽  
pp. 3806-3812
Author(s):  
Truyen Hai Dang ◽  
Sangmo Kim ◽  
Maro Kim ◽  
Chung Wung Bark

Perovskite solar cells have been attracting extensive attention because of their superior photovoltaic performances and lower costs as compared to those of prevailing photovoltaic technologies. There are four main interfaces in perovskite solar cells: flourine-doped tin oxide/electron transport layer, electron transport layer/perovskite layer, perovskite layer/hole transport layer, and hole transport layer/metal electrode. Among them, the interface between the perovskite layer (general formula RPbX3) and electron transport layer significantly affects the power conversion efficiency. In this study, a layer of TiO2, which is the most popular metal oxides used for perovskite solar cells applications, was deposited as the electron transport layer. To enhance the perovskite solar cells performance, surface treatment was performed with TiCl4 (80 mM). To investigate the effect of TiCl4 treatment, ultraviolet-visible spectroscopy was performed on the perovskite film. Atomic force microscopy, X-ray diffraction, scanning electron microscopy and performance of perovskite solar cells have been also evaluated in this paper. The results indicated that the TiCl4 treatment significantly improved the perovskite solar cells performance.



Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 404
Author(s):  
Abdul Sami ◽  
Arsalan Ansari ◽  
Muhammad Dawood Idrees ◽  
Muhammad Musharraf Alam ◽  
Junaid Imtiaz

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage Voc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (Vbi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.



Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2191
Author(s):  
Xiaolan Wang ◽  
Xiaoping Zou ◽  
Jialin Zhu ◽  
Chunqian Zhang ◽  
Jin Cheng ◽  
...  

It is crucial to find a good material as a hole transport layer (HTL) to improve the performance of perovskite solar cells (PSCs), devices with an inverted structure. Polyethylene dioxythiophene-poly (styrene sulfonate) (PEDOT:PSS) and inorganic nickel oxide (NiOx) have become hotspots in the study of hole transport materials in PSCs on account of their excellent properties. In our research, NiOx and PEDOT: PSS, two kinds of hole transport materials, were prepared and compared to study the impact of the bottom layer on the light absorption and morphology of perovskite layer. By the way, some experimental parameters are simulated by wx Analysis of Microelectronic and Photonic Structures (wxAMPS). In addition, thin interfacial layers with deep capture levels and high capture cross sections were inserted to simulate the degradation of the interface between light absorption layer and PEDOT:PSS. This work realizes the combination of experiment and simulation. Exploring the mechanism of the influence of functional layer parameters plays a vital part in the performance of devices by establishing the system design. It can be found that the perovskite film growing on NiOx has a stronger light absorption capacity, which makes the best open-circuit voltage of 0.98 V, short-circuit current density of 24.55 mA/cm2, and power conversion efficiency of 20.01%.



Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 978
Author(s):  
Chaoqun Lu ◽  
Weijia Zhang ◽  
Zhaoyi Jiang ◽  
Yulong Zhang ◽  
Cong Ni

The hole transport layer (HTL) is one of the main factors affecting the efficiency and stability of perovskite solar cells (PSCs). However, obtaining HTLs with the desired properties through current preparation techniques remains a challenge. In the present study, we propose a new method which can be used to achieve a double-layer HTL, by inserting a CuI layer between the perovskite layer and Spiro-OMeTAD layer via a solution spin coating process. The CuI layer deposited on the surface of the perovskite film directly covers the rough perovskite surface, covering the surface defects of the perovskite, while a layer of CuI film avoids the defects caused by Spiro-OMetad pinholes. The double-layer HTLs improve roughness and reduce charge recombination of the Spiro-OMeTAD layer, thereby resulting in superior hole extraction capabilities and faster hole mobility. The CuI/Spiro-OMeTAD double-layer HTLs-based devices were prepared in N2 gloveboxes and obtained an optimized PCE (photoelectric conversion efficiency) of 17.44%. Furthermore, their stability was improved due to the barrier effect of the inorganic CuI layer on the entry of air and moisture into the perovskite layer. The results demonstrate that another deposited CuI film is a promising method for realizing high-performance and air-stable PSCs.



2019 ◽  
Vol 5 (2) ◽  
pp. eaav2012 ◽  
Author(s):  
Mojtaba Abdi-Jalebi ◽  
M. Ibrahim Dar ◽  
Satyaprasad P. Senanayak ◽  
Aditya Sadhanala ◽  
Zahra Andaji-Garmaroudi ◽  
...  

One source of instability in perovskite solar cells (PSCs) is interfacial defects, particularly those that exist between the perovskite and the hole transport layer (HTL). We demonstrate that thermally evaporated dopant-free tetracene (120 nm) on top of the perovskite layer, capped with a lithium-doped Spiro-OMeTAD layer (200 nm) and top gold electrode, offers an excellent hole-extracting stack with minimal interfacial defect levels. For a perovskite layer interfaced between these graded HTLs and a mesoporous TiO2 electron-extracting layer, its photoluminescence yield reaches 15% compared to 5% for the perovskite layer interfaced between TiO2 and Spiro-OMeTAD alone. For PSCs with graded HTL structure, we demonstrate efficiency of up to 21.6% and an extended power output of over 550 hours of continuous illumination at AM1.5G, retaining more than 90% of the initial performance and thus validating our approach. Our findings represent a breakthrough in the construction of stable PSCs with minimized nonradiative losses.



2018 ◽  
Vol 6 (29) ◽  
pp. 14255-14261 ◽  
Author(s):  
Huan Li ◽  
Guoqing Tong ◽  
Taotao Chen ◽  
Hanwen Zhu ◽  
Guopeng Li ◽  
...  

A derivative-phase CsPb2Br5 is introduced into inorganic perovskite solar cells, which will effectively eliminate interface defects, lower the energy barrier of electron transport layer and suppress the recombination at the interface of hole transport layer in the devices.



Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1227 ◽  
Author(s):  
Byung Kim ◽  
Woongsik Jang ◽  
Dong Wang

Nickel oxide (NiOx)–based perovskite solar cells (PSCs) have recently gained considerable interest, and exhibit above 20% photovoltaic efficiency. However, the reported syntheses of NiOx sol-gel used toxic chemicals for the catalysts during synthesis, which resulted in a high-temperature annealing requirement to remove the organic catalysts (ligands). Herein, we report a facile “NiOx sol-gel depending on the chain length of various solvents” method that eschews toxic catalysts, to confirm the effect of different types of organic solvents on NiOx synthesis. The optimized conditions of the method resulted in better morphology and an increase in the crystallinity of the perovskite layer. Furthermore, the use of the optimized organic solvent improved the absorbance of the photoactive layer in the PSC device. To compare the electrical properties, a PSC was prepared with a p-i-n structure, and the optimized divalent alcohol-based NiOx as the hole transport layer. This improved the charge transport compared with that for the typical 1,2-ethanediol (ethylene glycol) used in earlier studies. Finally, the optimized solvent-based NiOx enhanced device performance by increasing the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF), compared with those of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)–based devices.



2019 ◽  
Vol 74 (8) ◽  
pp. 665-672 ◽  
Author(s):  
Julian Höcker ◽  
David Kiermasch ◽  
Philipp Rieder ◽  
Kristofer Tvingstedt ◽  
Andreas Baumann ◽  
...  

AbstractThe organic and hydrophobic polymer poly[N, N′-bis(4-butilphenyl)-N, N′-bis(phenyl)-benzidine] (polyTPD) represents a promising hole transport layer (HTL) for perovskite photovoltaics due to its suitable energy levels, whereby its highest occupied molecular orbital level matches well with the valence band level of methylammonium lead triiodide (CH3NH3PbI3, MAPbI3) perovskite. However, processing a perovskite layer from the solution on the surface of this organic material, is found to be difficult due to the surface properties of the latter. In this study, we evaluate efficient p-i-n type MAPbI3 perovskite solar cells employing differently processed polyTPD layers. We found that the surface coverage of the MAPbI3 perovskite layer strongly depends on the preparation method of the underlying polyTPD layer. By varying the solvents for the polyTPD precursor, its concentration, and by applying an optimised two-step perovskite deposition technique we increased both the surface coverage of the perovskite layer as well as the power conversion efficiency (PCE) of the corresponding solar cell devices. Our simple solvent-engineering approach demonstrates that no further interface modifications are needed for a successful preparation of efficient planar photovoltaic devices with PCEs in the range of 15 %–16 %.



Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 682 ◽  
Author(s):  
Chien-Jui Cheng ◽  
Rathinam Balamurugan ◽  
Bo-Tau Liu

In this study, we incorporated silver nanowires (AgNWs) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for inverted perovskite solar cells (PVSCs). The effect of AgNW incorporation on the perovskite crystallization, charge transfer, and power conversion efficiency (PCE) of PVSCs were analyzed and discussed. Compared with neat PEDOT:PSS HTL, incorporation of few AgNWs into PEDOT:PSS can significantly enhance the PCE by 25%. However, the AgNW incorporation may result in performance overestimation due to the lateral charge transfer. The corrosion of AgNWs with a perovskite layer was discussed. Too much AgNW incorporation may lead to defects on the interface between the HTL and the perovskite layer. An extra PEDOT:PSS layer over the pristine PEDOT:PSS-AgNW layer can prevent AgNWs from corrosion by iodide ions.



Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2151
Author(s):  
Syed Shah ◽  
Muhammad Sayyad ◽  
Karim Khan ◽  
Jinghua Sun ◽  
Zhongyi Guo

Application of MXene materials in perovskite solar cells (PSCs) has attracted considerable attention owing to their supreme electrical conductivity, excellent carrier mobility, adjustable surface functional groups, excellent transparency and superior mechanical properties. This article reviews the progress made so far in using Ti3C2Tx MXene materials in the building blocks of perovskite solar cells such as electrodes, hole transport layer (HTL), electron transport layer (ETL) and perovskite photoactive layer. Moreover, we provide an outlook on the exciting opportunities this recently developed field offers, and the challenges faced in effectively incorporating MXene materials in the building blocks of PSCs for better operational stability and enhanced performance.



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