Hai-Qiao Wang

High-Performance Polymer Solar Cells with PCE of 10.42% via Al-Doped ZnO Cathode Interlayer

High-performance polymer solar cells incorporating a low-temperature-processed aluminum-doped zinc oxide (AZO) cathode interlayer are constructed with power conversion efficiency (PCE) of 10.42% based on PTB7-Th:PC71 BM blends (insensitive to the AZO thickness). Moreover, flexible devices on poly(ethylene terephthalate)/indium tin oxide substrates with PCE of 8.93% are also obtained, and welldistributed efficiency and good device stability are demonstrated as well.

Improved Device Performance of Polymer Solar Cells by Using a Thin Light-harvesting-Complex Modified ZnO Film as the Cathode Interlayer

In this study, a high-performance inverted polymer solar cell (PSC) has been fabricated by incorporating a zinc oxide (ZnO)/light-harvesting complex II (LHCII) stacked structure as the cathode interlayer. The LHCII not only smoothens the film surface of ZnO, improves the contact between ZnO and the photoactive layer, but also suppresses the charge carrier recombination at the interface, hence all the device parameters of PTB7-based solar cells are simultaneously improved, yielding higher power conversion efficiency (PCE) up to 9.01% compared with the control one (PCE 8.01%). And the thin LHCII modification layer also presents similar positive effects in the PTB7-Th:PC71BM system (PCE from 8.31% to 9.60%). These results put forward a facile approach to the interfacial modification in high-performance PSCs and provide new insight into developing and utilizing inexpensive and environmentally friendly materials from the fields of biological photosynthesis.

Regular Organic Solar Cells with Efficiency over 10% and Promoted Stability by Ligand- and Thermal Annealing-Free Al-Doped ZnO Cathode Interlayer

Landmark power conversion efficiency (PCE) over 10% has been accomplished in the past year for single‐junction organic solar cell (OSCs), suggesting a promising potential application of this technology. However, most of the high efficient OSCs are based on inverted configuration. Regular structure OSCs with both high efficiency and good stability are still rarely reported to date. In this work, by utilizing a new designed ligand‐free and non‐thermal‐annealing‐treated Al‐doped ZnO cathode interlayer, high efficiency and greatly improved stability are simultaneously realized in regular OSCs. The highest PCE of 10.14% is accomplished for single‐junction regular OSCs with active blend of poly [[2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b]dithiophene][3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno [3,4‐b]thiophenediyl]] (PTB7‐Th):[6,6]‐phenyl C71‐butyric acid methyl ester (PC71BM). Excellent device stability is confirmed as well, by keeping 90% of its initial PCE value after 135 d in N2, and 80% of its initial PCE value after 15 d in ambient air, respectively. Furthermore, the applicability of the designed interlayer in regular OSCs is demonstrated by other active blend systems, including the nonfullerene material. This work highlights that high efficiency and good stability can be realized simultaneously in regular OSCs as well, and will provide referential strategy and methodology for this target.

Improving Efficiency and Reproducibility of Perovskite Solar Cells through Aggregation Control in Polyelectrolytes Hole Transport Layer

Here, we report that the performance of perovskite solar cells (PSCs) can be improved by aggregation control in polyelectrolytes interlayer. Through counterions tailoring and solvent optimization, the strong aggregation of polyelectrolytes P3CT-Na can be broken up by P3CT-CH3NH2. When using P3CT-CH3NH2 to replace P3CT-Na as hole transport layer, the average efficiency is greatly improved from 16.9 to 18.9% (highest 19.6%). Importantly, efficiency over 15% is obtained in 1 cm2 devices with P3CT-CH3NH2, ∼50% higher than that with P3CT-Na (10.3%). Our work demonstrates the important role of aggregation control in polyelectrolytes interlayer, providing new opportunities to promote its application in PSCs.

High-Performance Polymer Solar Cells with Zinc Sulfide-Phenanthroline Derivatives as the Hybrid Cathode Interlayers.

Environmentally benign hybrid interlayers are prepared by modifying the zinc sulfide (ZnS) with phenanthroline/derivatives and utilized in inverted polymer solar cells (PSCs). Performances of the inverted PSCs are improved enormously by incorporating these hybrid interlayers, as which can effectively improve the energy level alignment, electron mobility, surface morphology, and interfacial contact. Greatly improved power conversion efficiencies (PCEs) of 7.79%, 8.00%, 7.47%, and 7.56% are achieved with these hybrid interlayers ZnS-BCP, ZnS-Bphen, ZnS-Mphen, and ZnS-Phen, respectively, compared to the PCE of 2.99% of the reference ZnS-based device, based on PTB7:PC71BM active layer. Our results demonstrate that hybrid interfacial materials comprising inorganic and organic semiconductor possess promising potential to improve the performance of organic electronic devices, and set an example to develop this novel class of interfacial materials for electronic devices.

CdS–phenanthroline derivative hybrid cathode interlayers for high performance inverted organic solar cells

Phenanthroline based organic semiconductors (BCP, Bphen, Mphen, and Phen) are used to hybrid with CdS as cathode interlayers in inverted organic solar cells (OSCs). We observed that selecting the polar solvent and hydrophobic interlayers with a diphenyl group could improve the performance of the organic photovoltaic devices. The modification to CdS can effectively improve its electron mobility, film morphology, interfacial contact, and energy level alignment, which finally leads to a significant enhancement of device performance. Through incorporating the CdS–P hybrids (CdS–BCP, CdS–Bphen, CdS–Mphen, and CdS–Phen) as cathode buffer layers, the device PCE (PTB7u2006:u2006PC71BM as the active layer) is greatly improved from 3.09% to 8.36, 7.84, 6.69, and 6.57%, respectively, compared with devices fabricated on the pristine CdS interlayer. These results indicate that the common inorganic semiconductor like CdS can be modified using some organic semiconductors to produce general applicable electron transport layers applied in OSCs. Our work puts forward new insights for the development of new interface modification materials and fabrication of high efficiency devices.

In-situ cross-linking strategy for efficient and operationally stable methylammoniun lead iodide solar cells

Long-term operational stability is the foremost issue delaying the commercialization of perovskite solar cells (PSCs). Here we demonstrate an in-situ cross-linking strategy for operationally stable inverted MAPbI3 PSCs through the incorporation of a cross-linkable organic small molecule additive trimethylolpropane triacrylate (TMTA) into perovskite films. TMTA can chemically anchor to grain boundaries and then in-situ cross-link to a robust continuous network polymer after thermal treatment, thus enhancing the thermal, water-resisting and light-resisting properties of organic/perovskite films. As a result, the cross-linked PSCs exhibit 590-fold improvement in operational stability, retaining nearly 80% of their initial efficiency after continuous power output for 400u2009h at maximum power point under full-sun AM 1.5u2009G illumination of Xenon lamp without any UV-filter. In addition, under moisture or thermal (85u2009°C) conditions, cross-linked TMTA-based PSCs also show excellent stability with over 90% of their initial or post burn-in efficiency after aging for over 1000u2009h.The stability of perovskite solar cell remains the biggest challenge that hinders its commercialization. Here Li et al. incorporate crosslinkable molecules to form a crosslinked perovskite film and increase the device operational stability by 590 times to 400u2009h under standard Xenon lamp without filters.

The study of colloidal lead bromide perovskite nanocrystals and its application in hybrid solar cells

In this study, we investigated inorganic cesium lead halide perovskite semiconductor and tested its application in photovoltaics. Highly crystalline material was synthesized by two different approaches, including a high temperature route and a low temperature method. Inorganic-polymer hybrid solar cells based on solution-deposited layers of CsPbBr3 nanocrystals were successfully fabricated in ambient, with and without post treatments. The solar cells employing nanocrystals with short ligands, obtained from low temperature route, outperformed the devices with long ligands. The devices exhibited an efficiency up to 1.16%, with an open circuit voltage (Voc) of 0.87xa0V, a fill factor of 56.2% and a short-circuit current density (Jsc) of 2.38xa0mA/cm2.

High-Performance All-Polymer Solar Cells with a High Fill Factor and a Broad Tolerance to the Donor/Acceptor Ratio

Manipulating the donor/acceptor (D/A) weight ratio is a critical route to produce highly efficient polymer solar cells (PSCs). However, most of the reported device performances are strongly sensitive to the blend ratio. In this work, highly efficient all-PSCs based on PBDB-T:N2200 active layer have been achieved, presenting impressive photovoltaic performance with high tolerance to wide D/A ratios ranging from 1:1 to 9:1, thus providing a broad blend ratio processing window for future practical production. In particular, the optimal device delivers the champion power conversion efficiency (PCE) of 8.61% with an outstanding fill factor (FF) of up to 75.4%, which is one of the highest FF values for the reported binary all-PSCs. Comprehensive morphological, electrical, and mechanism analysis together pointed out that the remarkable device performance are derived from the favorable interpenetrating network morphology, efficient exciton generation/dissociation, well-balanced carrier transport, and reduced bimolecular recombination. Moreover, compared to the small molecule-based and fullerene-based PSC counterparts, the all-PSCs demonstrate an excellent resilience to the D/A ratio, maintaining over 50% of the maximum PCE at a ratio of 49:1 with an extremely low acceptor content. These results depict a bright prospect of the developed all-PSCs for promising applications as flexible and scalable optoelectronic devices.

Boronization during the first plasma operation on EAST

Both ion cyclotron rf and glow discharge boronization have been successfully used for wall conditioning on EAST tokamak device. The whole process is monitored continuously by residual gas analyzer and film thickness monitor. These diagnostics provide detailed information about the boronization. High hydrogen inventory level observed after boronization maybe due to the boronization material used (C2B10H12). Ion cyclontron rf conditioning is proved to be an efficient wall conditioning method for superconducting device because it could be carried out under toroidal magnetic field. In this paper, the procedure of boronization is described, and subsequently sample analysis and the effect on plasma operation are introduced. Conclusion is given at the end.