Quantum confined structure-based solar cell is promising two folds increment of the maximum theoretical photovoltaic conversion efficiency i.e., > 60% in comparison with that of the bulk analogs e.g., silicon-based and dye sensitized solar cell (ca. 32% of maximum theoretical efficiency). The key to the significant increment is the ability of the fluorophore to exhibit multiple exciton generation upon absorption photon with sufficient energy. Small size of lead chalcogenides (PbS, PbSe, PbTe) crystals have been reported and proven experimentally could exhibit this unique property. We have investigated few clusters of narrow bandgap lead chalcogenides nanocrystals i.e., (PbS)n, (PbSe)n and (PbTe)n; which n = 4 - 80. The cluster models were optimized using quantum chemical calculations to the lowest energy geometry at B3LYP/lanl2dz level of theory. The predicted realistic (PbS)₈₀, (PbSe)₅₀, and (PbTe)₇₄ clusters with the size, and bandgap of 4.58 nm (2.00 eV), 4.03 nm (1.51 eV), and 4.84 nm (1.55 eV) are smaller than that of their exciton Bohr radius i.e., 5.01, 13.1, and 24.8 nm respectively. Therefore, the occurrence of multi exciton generation in the clusters is hypothesized upon absorption of photon with E_photon = 2E_g.

基于量子约束结构的太阳能电池有望将最大理论光伏转换效率提高两倍，即与硅基和染料敏化太阳能电池等大容量类似物相比，提高> 60％（约为最大理论光伏电池效率的32％）效率）。显着增加的关键是荧光团在吸收具有足够能量的光子后表现出多种激子产生的能力。已经报道了小尺寸的硫属元素铅（PbS，PbSe，PbTe）晶体，并通过实验证明可以表现出这种独特的性质。我们研究了窄带隙铅硫族化物纳米晶体的几个簇，即（PbS）n，（PbSe）n和（PbTe）n；哪n = 4-80。使用量子化学计算将群集模型优化为理论B3LYP / lan12dz最低能量几何。预测的实际（PbS）₈₀，（PbSe）₅₀和（PbTe）₇₄簇的尺寸和带隙分别为4.58 nm（2.00 eV），4.03 nm（1.51 eV）和4.84 nm（1.55 eV）小于的激子玻尔半径分别为5.01、13.1和24.8 nm。因此，假设在吸收了E_光子= 2 E _g的光子后，会在簇中产生多激子。