平面型给-受体共轭聚合物的合成及在体异质结聚合物太阳能电池中的应用

设计合成了主链为聚2,8-{5,11-二烷基吲哚[3,2-b]咔唑}-4,7[2,5-噻吩]-二-5,6-二烷氧基-2,1,3-苯并噻二唑, 具有不同侧链的2种平面型给-受体共轭聚合物(QP-2和QP-3), 研究了其热学、光物理和光伏性质. 用聚合物-PC₇₁BM([6,6]-苯基C₇₁丁酸甲酯)共混物作为活性层构筑了本体异质结聚合物太阳能电池. 其中以QP-3为给体、以PC₇₁BM为受体的光伏电池能量转换效率最高达到2.59%, 开路电压为0.72 V, 短路电流为9.24 mA/cm², 填充因子为0.38. XRD结果表明, 平面型共轭聚合物具有较好的结晶性, 原子力显微镜(AFM)显示平面型共轭聚合物易于发生微观相分离.     

Synthesis and photovoltaic properties of poly(p-phenylenevinylene) derivatives with two triphenylamine and bithiophene conjugated side chains

Two soluble poly(p-phenylenevinylene) derivatives (PPVs) with two bithiophenes as conjugated side chains, P1 and P2, were synthesized and characterized for application in polymer solar cells (PSCs). The thermal, photophysical, electrochemical and photovoltaic properties of the PPVs were investigated and compared with those of the PPVs without conjugated side chains. Bulk heterojunction solar cell devices are fabricated using the copolymers as the electron donor and PCBM ([6,6]-phenyl-C₆₁-butyric acid methyl ester) as the electron acceptor. The power conversion efficiencies (η) based on the P1 and P2 are 1.1% and 1.41% under AM 1.5 illumination (100 mW/cm²), respectively.     

Effects of Mn substitution on the structure and properties of chalcopyrite-type CuInSe2

Mn-doped CuInSe₂ compounds (CuIn_1−xMn_xSe₂, x=0.0125–0.20 and Cu_1−yIn_1−yMn_2ySe₂, 2y=0.0125–0.60) were synthesized by high-temperature solid-state reactions. Single phase materials with chalcopyrite structure persist up to 0.10 and 0.20 doping for CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂, respectively. The chalcopyrite and sphalerite phases co-exist in the Cu_1−yIn_1−yMn_2ySe₂ system for 2y=0.25–0.50. Attempts to introduce greater manganese content, x=0.15–0.20 for CuIn_1−xMn_xSe₂ and 2y=0.60 for Cu_1−yIn_1−yMn_2ySe₂, result in partial phase segregation. For the single-phase samples, the lattice parameters of both systems increase linearly with manganese concentration and thus follow Vegard's law. The temperature of the chalcopyrite–sphalerite phase transition is decreased by manganese substitution for all single-phase samples. The bandgap of the materials remains around 0.9 eV. Additionally, the Mn-doped CuInSe₂ compounds display paramagnetic behavior, whereas pure CuInSe₂ is diamagnetic at 5–300 K. All the CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂ compounds with chalcopyrite structure show antiferromagnetic coupling and measured effective magnetic moments up to 5.8 μ_B/Mn.     

苝二酰亚胺/聚噻吩复合膜的光电性能研究

在有机光电材料领域,光稳定性好、光谱吸收范围宽、光电转换效率高的材料是研究工作者不断追求的目标．近年来,导电聚合物研究的不断进展使得开发低成本太阳电池成为可能．共轭导电高分子材料由于在一定程度上同时具有聚合物的柔韧性和可加工性、以及无机半导体特性或金属导电性,因而具有巨大的潜在商业应用价值．     

PbS纳米粒子与全共轭高分子的自组装膜原位复合及其光电转换性质

无机纳米粒子因其在催化、磁学、光子学等方面的特殊性质而越来越受到关注,纳米粒子粒径及分布可以人为控制,由此能够改变与有机聚合物所形成的纳米复合材料性能,在各种无机纳米粒子／有机聚合物复合材料制备方法中,纳米反应器(Nanoreactor)技术正日益受到关注,与常规的作为化学反应特定场所的化学反应器不同,纳米反应器不是一般的具体的机械设备,     

Improving photovoltaic properties via electric-field-induced orientation of conjugated polymer

A high electric field is applied to polarize the undoped MEH-PPV and the MEH-PPV: C₆₀ composite thin film in the process of spin-coating. Due to the polarization causing the orientation of the MEH-PPV chains, the resulting thin-film devices show improved photovoltaic properties. For undoped MEH-PPV devices, oriented under the electric field of 6×10³ V cm⁻¹, the short-circuit current and the external quantum efficiency (EQE) are enhanced by a factor of 2.5 and 2, respectively. For MEH-PPV–fullerene composite devices, oriented under the same field, the and the EQE are improved by a factor of 1.8 and 1.7, respectively.     

Theoretical study on photoelectric properties of lead-free mixed inorganic perovskite RbGe1-xSnxI3

The recent discoveries of lead-free halide perovskites have come into notice as promising photovoltaic materials due to their high solar-to-electrical efficiency conversion. However, these perovskites suffer from large effective masses, wide band gap and affected photovoltaic performance. It is well known that it is an effective means to overcome the above shortcomings by changing the metallic ion concentration and position for the inorganic perovskite. Herein, we study the geometrical, electronic, and optical properties of RbGe_1-xSn_xI₃ with various compositions of metal atoms by performing the Density Functional Theory (DFT). Besides, we systematically investigate how the doping positions of stannum (Sn) atoms affect the electronic structure by taking mixed metal RbGe_0.50Sn_0.50I₃ compound as an example. The results show that RbGe_1-xSn_xI₃ exhibits the semiconducting property with the tunable direct band gaps by changing its proportions. Compared to other two doping positions in the perovskite RbGe_0.50Sn_0.50I₃, the configuration with Sn atom at equator plane has better mobility of electron and optical absorption properties. Our works demonstrate that the modification of metal concentration and position will modulate the optoelectronic performance and photovoltaic properties of mixed metal perovskites.     

ZnO/TiO2 core–shell heterojunction for CdS and PbS quantum dot-cosensitized solar cells

ZnO nanorods (NRs) with regular morphology were prepared through hydrothermal method, and the TiO₂ shell was assembled onto the surface of ZnO NRs by spin coating to the ZnO/TiO₂ core–shell heterojunction. CdS and PbS quantum dots (QDs) were used to cosensitize the ZnO/TiO₂ nanostructure by direct adsorption (DA) and successive ionic layer adsorption and reaction, respectively. SEM, TEM, and HRTEM images show that the samples possessed a rough surface and four lattice fringes indicating the successful synthesis of the ZnO/TiO₂/CdS/PbS composite structure. The ZnO/TiO₂(10T)/CdS/PbS sample showed a high absorption intensity at a broad range of wavelength to visible light region. The ZnO/TiO₂(10T)/CdS/PbS photoelectrode with QDSSCs showed the highest IPCE of 36.04% and photoelectric efficiency (η) of 1.59%; these values increased by approximately 550% and 150% compared with those of unsensitized ZnO (0.29%) and ZnO/TiO₂(10T) (1.04%) and about 146% and 120% compared with those of ZnO/TiO₂(10T)/CdS and ZnO/TiO₂(10T)/PbS, respectively. The fill factor was 0.36, and the photocurrent density (J_sc) and open circuit voltage (V_oc) reached the maximum values of 9.73 mA cm⁻² and 0.46 V, respectively.     

Electrical and photovoltaic characteristics of sodium copper chlorophyllin/n-type silicon heterojunctions

Heterojunctions of p-type sodium copper chlorophyllin (p-SCC)/n-type silicon (n-Si) were prepared by deposition of p-SCC film on n-Si wafers using spray-pyrolysis technique. Current-voltage and capacitance-voltage measurements of Au/p-SCC/n-Si/In heterojunctions were performed to discuss the electrical properties of these heterostructures. Rectifying characteristics were observed, which are definitely of the diode type. The current-voltage measurements suggest that the forward current in these junctions involves tunnelling and the results showed that the forward current can be explained by a multi-tunnelling capture-emission model in which the electron emission process dominates the carrier transport mechanism. On the other hand, the reverse current is probably limited by the same conduction process. The capacitance-voltage behavior indicates an abrupt heterojunction model is valid for Au/p-SCC/n-Si/In heterojunctions and the junction parameters such as, built-in potential, V_D, carrier concentration, N, the width of depletion layer, W, were obtained. The temperature and frequency dependence of the measured capacitance were also studied. The loaded I-V characteristics under white illumination provided by tungsten lamp (80 mW/cm²) give values of 400 mV, 0.9 mA, 0.38 and 1.7% for the open-circuit voltage, V_oc, the short-circuit current, I_sc, the fill factor, FF, and conversion efficiency, η, respectively.     

Higher-order space-charge field effects on the self-deflection of photovoltaic dark spatial solitons

We investigate theoretically the effects of higher-order space-charge field on the self-deflection of photovoltaic dark spatial solitons by numerical method under steady-state conditions. The expression for an induced space-charge electric field, including higher-order space-charge field terms is obtained. Numerical results indicate that photovoltaic dark solitons possess self-deflection process during propagation, and the solitons always bend in the direction of the c-axis of the crystal. The self-deflection of dark solitons can experience considerable increase especially in the regime of high photovoltaic field strengths. Relevant examples are provided.