Herein, the fabrication of a lead-free cesium germanium halide perovskite produced via a simple solvothermal process is reported for the first time. By tuning the composition of the CsGeX 3 quantum rods, a power conversion efficiency of 4.92% under AM 1.5 G was achieved.The global need for renewable and "green" energy alternatives continues to spur on research in low-cost and high-efficiency photovoltaic devices. Completely inorganic CsPbX 3 (X ¼ I, Br, Cl) perovskites constitute one kind of perovskite material and have been considered to be probable substitutes for organicinorganic perovskites.1,2 The hybrid, all-inorganic lead halide perovskites have generated enormous attention in the photovoltaic community due to their surprisingly rapid improvements in power conversion efficiency. 3,4While recent investigations have been mostly focused on hybrid organicinorganic compounds, the study of their inorganic analogues, such as ABX 3 (A ¼ Rb, Cs; B ¼ Ge, Sn, Pb; X ¼ Cl, Br, I), has been limited.5 However, the lead component is toxic and hence of high concern for human health, and can cause environmental damage, particularly because of its chemical stability.6,7 By replacing the lead component with germanium at the B-site, a lead-free perovskite can be formed, obviating the pollution problems and hence being environmentally friendly. Replacing unsafe lead in perovskites is essential in order to expand their applications. As a result, there has been a great deal of interest in replacing lead with nontoxic metals such as tin, bismuth, and germanium. 8-10Over the past several years, considerable advances have been made toward the synthesis of colloidal semiconductor nanorods or nanobers with diameters sufficiently small to produce a quantum connement of charge carriers. Semiconductor quantum rods (QRs) show properties between zero-dimensional quantum dots (QDs) and one-dimensional quantum wires. 11-13Per unit mass, QR volumes are larger than QD volumes and therefore have signicantly larger per-particle absorbance cross sections.14 This feature would be expected to increase the optical density of electrodes covered by up to a single layer of QR nanoparticles and therefore improve light harvesting. QRs are of great interest for fundamental research and are highly promising novel materials for new technologies.15,16 However, QR properties also depend on the quality of their internal crystal structure and may also exhibit decreased Auger recombination rates compared to those of quantum dots, 17 which makes them potentially useful for advanced optoelectronic devices. Many modern methods have been developed for the synthesis of one-dimensional QRs.18,19 However, these preparation processes oen require a relatively high temperature and vacuum, are complex, etc., while solvothermal methods offer great advantages such as low cost and exibility. [20][21][22] In this research we demonstrated a simple, rapid, and green solvothermal synthesis of high-quality lead-free perovskite-type CsGeX 3 with a uniform QR-shaped structure,...

Chalcopyrite quaternary semiconductor Cu(In(x)B(1-x))Se(2) nanocrystals have been successfully prepared via a relatively simple and convenient solvothermal route. The effect of different solvents on the formation of the product also indicates that diethylenetriamine is the optimal solvent for this reaction. The device parameters for a single junction Cu(In(x)B(1-x))Se(2) solar cell under AM1.5G are as follows: an open circuit voltage of 265 mV, a short-circuit current of 25.90 mA/cm(2), a fill factor of 34%, and a power conversion efficiency of 2.34%. Based on a series of comparative experiments under different reaction conditions, the probable formation mechanism of crystal Cu(In(x)B(1-x))Se(2) nanorods is proposed.

No abstract

No abstract