Optimizing thienothiophene chain lengths of D–π–D hole transport materials in perovskite solar cells for improving energy levels and hole mobility

2017 ◽  
Vol 5 (38) ◽  
pp. 10055-10060 ◽  
Author(s):  
Wei-Jie Chi ◽  
Dao-Yuan Zheng ◽  
Xiao-Fang Chen ◽  
Ze-Sheng Li

The energy levels and hole mobility of D–π–D hole transport materials can be optimized by changing the thienothiophene chain lengths.

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.


2016 ◽  
Vol 18 (39) ◽  
pp. 27073-27077 ◽  
Author(s):  
Wei-Jie Chi ◽  
Ping-Ping Sun ◽  
Ze-Sheng Li

meta-Substitution is more beneficial to reduce HOMO levels compared with ortho- and para-substitution, while the hole mobility can be improved by ortho-substitution.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3128
Author(s):  
Laila M. Nhari ◽  
Reda M. El-Shishtawy ◽  
Qiuchen Lu ◽  
Yuanzuo Li ◽  
Abdullah M. Asiri

Three novel triarylamine-based electron-rich chromophores were synthesized and fully characterized. Compound 1 and Compound 2 were designed with electron-rich triphenylamine skeleton bearing two and four decyloxy groups namely, 3,4-bis(decyloxy)-N,N-diphenylaniline and N-(3,4-bis(decyloxy)phenyl)-3,4-bis(decyloxy)-N-phenylaniline, respectively. The well-known electron-rich phenothiazine was introduced to diphenylamine moiety through a thiazole ring to form N,N-bis(3,4-bis(decyloxy)phenyl)-5-(10H-phenothiazin-2-yl)thiazol−2-amine (Compound 3). These three novel compounds were fully characterized and their UV–vis absorption indicated their transparency as a favorable property for hole transport materials (HTMs) suitable for perovskite solar cells. Cyclic voltammetry measurements revealed that the HOMO energy levels were in the range 5.00–5.16 eV for all compounds, indicating their suitability with the HOMO energy level of the perovskite photosensitizer. Density functional theory (DFT) and time-dependent DFT (TD-DFT) have been used to investigate the possibility of the synthesized compounds to be utilized as HTMs for perovskite solar cells (PSCs). The computational investigation revealed that the hole mobility of Compound 1 was 1.08 × 10–2 cm2 V−1 s−1, and the substitution with two additional dialkoxy groups on the second phenyl ring as represented by Compound 2 significantly boosted the hole mobility to reach the value 4.21 × 10–2 cm2V−1 s−1. On the other hand, Compound 3, in which the third phenyl group was replaced by a thiazole-based phenothiazine, the value of hole mobility decreased to reach 5.93 × 10–5 cm2 V−1 s−1. The overall results indicate that these three novel compounds could be promising HTMs for perovskite solar cells.


Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 354
Author(s):  
Shaoxi Wang ◽  
He Guan ◽  
Yue Yin ◽  
Chunfu Zhang

With the continuous development of solar cells, the perovskite solar cells (PSCs), whose hole transport layer plays a vital part in collection of photogenerated carriers, have been studied by many researchers. Interface transport layers are important for efficiency and stability enhancement. In this paper, we demonstrated that lithium (Li) and cobalt (Co) codoped in the novel inorganic hole transport layer named NiOx, which were deposited onto ITO substrates via solution methods at room temperature, can greatly enhance performance based on inverted structures of planar heterojunction PSCs. Compared to the pristine NiOx films, doping a certain amount of Li and Co can increase optical transparency, work function, electrical conductivity and hole mobility of NiOx film. Furthermore, experimental results certified that coating CH3NH3PbIxCl3−x perovskite films on Li and Co- NiOx electrode interlayer film can improve chemical stability and absorbing ability of sunlight than the pristine NiOx. Consequently, the power conversion efficiency (PCE) of PSCs has a great improvement from 14.1% to 18.7% when codoped with 10% Li and 5% Co in NiOx. Moreover, the short-circuit current density (Jsc) was increased from 20.09 mA/cm2 to 21.7 mA/cm2 and the fill factor (FF) was enhanced from 0.70 to 0.75 for the PSCs. The experiment results demonstrated that the Li and Co codoped NiOx can be a effective dopant to improve the performance of the PSCs.


2020 ◽  
Vol 240 ◽  
pp. 122058 ◽  
Author(s):  
Jiaren Guo ◽  
Yan Zhang ◽  
Wanlin Cai ◽  
Zemin Zhang ◽  
Rongxing He ◽  
...  

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 %.


2015 ◽  
Vol 3 (34) ◽  
pp. 17738-17746 ◽  
Author(s):  
Christopher Steck ◽  
Marius Franckevičius ◽  
Shaik Mohammed Zakeeruddin ◽  
Amaresh Mishra ◽  
Peter Bäuerle ◽  
...  

Heteropentacene-based A–D–A type hole transport materials with suitable frontier orbital energy levels were synthesized and used in perovskite solar cells showing power conversion efficiencies up to 11.4%.


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