Jinbiao Jia

Modulated CH 3 NH 3 PbI 3−x Br x film for efficient perovskite solar cells exceeding 18%

The organic-inorganic lead halide perovskite layer is a crucial factor for the high performance perovskite solar cell (PSC). We introduce CH3NH3Br in the precursor solution to prepare CH3NH3PbI3−xBrx hybrid perovskite, and an uniform perovskite layer with improved crystallinity and apparent grain contour is obtained, resulting in the significant improvement of photovoltaic performance of PSCs. The effects of CH3NH3Br on the perovskite morphology, crystallinity, absorption property, charge carrier dynamics and device characteristics are discussed, and the improvement of open circuit voltage of the device depended on Br doping is confirmed. Based on above, the device based on CH3NH3PbI2.86Br0.14 exhibits a champion power conversion efficiency (PCE) of 18.02%. This study represents an efficient method for high-performance perovskite solar cell by modulating CH3NH3PbI3−xBrx film.

An in situ polymerized PEDOT/Fe3O4 composite as a Pt-free counter electrode for highly efficient dye sensitized solar cells

3,4-Ethylenedioxy thiophene (EDOT) precursor solution doped by Fe3O4 was spin-casted onto fluorine doped tin oxide (FTO) glass and formed poly(3,4-ethylenedioxy thiophene) (PEDOT)/Fe3O4 hybrid films by an in situ polyreaction. The films were utilized as the counter electrode in dye sensitized solar cells (DSSCs). Photoelectric conversion efficiency (PCE) for DSSCs based on PEDOT/Fe3O4 varied with the content of Fe3O4 in the precursor solution. When the content of Fe3O4 was 2 mg ml−1 in the precursor solution (PEDOT/Fe3O4-2), the best performance (8.69%) was obtained. In comparison, that of a DSSC with a Pt counter electrode is 8.35%. According to the surface microtopography and electrochemical analysis, large active areas, consecutive electronic transmission channels and lower charge transfer resistance could be responsible for the high PCE.

Nickel selenide/reduced graphene oxide nanocomposite as counter electrode for high efficient dye-sensitized solar cells

Nickel selenide/reduced graphene oxide (Ni0.85Se/rGO) nanosheet composite is synthesized by a facile hydrothermal process and used as counter electrode (CE) for dye-sensitized solar cells (DSSC). The Ni0.85Se/rGO film spin-coated on FTO show prominent electrocatalytic activity toward I3-/I-. The electrocatalytic ability of Ni0.85Se/rGO film is verified by photocurrent-voltage curves, cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization curves. On account of its decent electrical conductivity and superior electrocatalytic activity, the DSSC using optimal Ni0.85Se/rGO CE achieves a power conversion efficiency (PCE) of 9.75%, while the DSSC based on sputtered Pt CE only obtains a PCE of 8.15%.

Efficient perovskite solar cells employing a simply-processed CdS electron transport layer

In this report, redispersable CdS nanoparticles are synthesized via a specific one-step solvothermal reaction and are employed as electron-selective materials for organometal halide perovskite solar cells. The as-synthesized CdS nanoparticles can be well re-dispersed in toluene to form a uniform and stable CdS ink. On this basis, a CdS electron-selective contact layer can be directly prepared by spin-coating CdS ink and without a further annealing process. The CdS electron-selective contact layer has high optical transmittance at visible wavelengths. Its electron extraction and transfer properties are also investigated using current density–voltage curves, incident photocurrent conversion efficiency, stabilized current density and photoluminescence spectra. The use of a CdS electron-selective contact layer in a planar perovskite solar cell equipped with a Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3 light-absorption layer results in a high power conversion efficiency of 16.5%.

High-Performance Molybdenum Diselenide Electrodes Used in Dye-Sensitized Solar Cells and Supercapacitors

Metal dichalcogenide has a layered structure, which is endowed with versatile and tunable photoelectrochemical properties. In this paper, molybdenum diselenide (MoSe2) is synthesized by the solvothermal method, and the as-synthesized MoSe2 shows microsphere hierarchical architecture composed of 2-D nanosheets. The electrochemical characterization indicates that the MoSe2 electrode has lower resistances and better electrocatalytic activity toward triiodide/iodide redox reaction than the traditional Pt electrode. Using the MoSe2 as a counter electrode in the dye-sensitized solar cell (DSSC), a high-power-conversion efficiency of 9.80% is achieved, outperforming the DSSC-based traditional Pt counter electrode (8.17%). Moreover, using the MoSe2 as an electrode in the supercapacitor, it displays a high specific capacitance of 272 F.g-1.

Annealing-Free Cr2O3 Electron-Selective Layer for Efficient Hybrid Perovskite Solar Cells

The electron-selective layer (ESL) plays a pivotal role in the performance of perovskite solar cells (PSCs). In this study, amorphous dispersible chromium oxide (Cr2 O3 ) nanosheets are synthesized by a facile solvothermal reaction, and a Cr2 O3 ESL is prepared by spin-coating Cr2 O3 ink on fluorine-doped tin oxide substrates without need for further annealing. By using Cr2 O3 as the electron-selective layer and Cs0.05 (MA0.17 FA0.83 )0.95 Pb(I0.83 Br0.17 )3 as the light-absorption layer, a planar hybrid perovskite solar cell is fabricated. The spin-coating speed is optimized, the structure and morphology of samples are observed, the photoelectrical properties of ESLs are characterized, and the photovoltaic behaviors of devices are measured. Results show that the as-prepared Cr2 O3 layer has high optical transmittance and superb electron extraction and carrier transport property. The planar hybrid PSC based on the optimized Cr2 O3 ESL achieves a power conversion efficiency of 16.23 %, which is comparable to devices based on a conventional high-temperature-calcined TiO2 ESL. These results demonstrate a low-cost and facile route to highly effective perovskite solar cells.