Hybrid pn-junction solar cells based on layers of inorganic nanocrystals and organic semiconductors: optimization of layer thickness by considering the width of the depletion region

Abstract

We report the formation and characterization of hybrid pn-junction solar cells based on a layer of copper diffused silver indium disulfide (AgInS2@Cu) nanoparticles and another layer of copper phthalocyanine (CuPc) molecules. With copper diffusion in the nanocrystals, their optical absorption and hence the activity of the hybrid pn-junction solar cells was extended towards the near-IR region. To decrease the particle-to-particle separation for improved carrier transport through the inorganic layer, we replaced the long-chain ligands of copper-diffused nanocrystals in each monolayer with short-ones. Under illumination, the hybrid pn-junctions yielded a higher short-circuit current as compared to the combined contribution of the Schottky junctions based on the components. A wider depletion region at the interface between the two active layers in the pn-junction device as compared to that of the Schottky junctions has been considered to analyze the results. Capacitance-voltage characteristics under a dark condition supported such a hypothesis. We also determined the width of the depletion region in the two layers separately so that a pn-junction could be formed with a tailored thickness of the two materials. Such a "fully-depleted" device resulted in an improved photovoltaic performance, primarily due to lessening of the internal resistance of the hybrid pn-junction solar cells.

Retracted Article: Facile fabrication of water-dispersible AgInS2 quantum dots and mesoporous AgInS2 nanospheres with visible photoluminescence

“…2a). 28 These results indicate that the products should be AgInS 2 nanocrystals. 30 The crystal microstructure of AgInS 2 QDs was characterized by XRD.…”

“…As displayed in Fig. [26][27][28][29] At different calcination temperatures, the absorption spectra and emission spectra of resultant mesoporous AgInS 2 nanospheres were recorded respectively ( Fig. Under excitation at 630 nm, the QDs present a sharp PL emission peak at 820 nm.…”

A new strategy for synthesizing AgInS2 quantum dots emitting brightly in near-infrared window for in vivo imaging

“…With a band gap of ~1.8 eV at room temperature, the AgInS 2 QDs can emit in the near-infrared region with high extinction coefficients, which offers an intriguing alternative for biological imaging applications 25 . So far, a variety of strategies have been established for the synthesis of AgInS 2 QDs [26][27][28][29] , most of which were carried out in organic phase and organic ligands were used as the capping agents for the QDs. Although…”

Oxide–organic heterostructures: a case study of charge transfer disturbance at a SnO2–copper phthalocyanine buried interface

“…49,51 Since these simulations are focused on the influence of organic adsorbates on the charge transfer, required results can be obtained using clusters with a good approximation without high complexity of the calculations. To model a SnO 2 surface covered with organic adsorbates, CH 3 groups were placed bound to the oxygen atoms, mimicking organic adsorbates changing the original Sn 3 O 4 (OH) 4 cluster to Sn 3 O 4 (CH 3 ) 4 [ Fig. 5(b)].…”

“…Hybrid heterojunctions created out of inorganic-organic material stacks are currently attracting more and more attention due to the number of technological applications. [1][2][3] Especially low-dimensional heterostructures with applications varying from photovoltaics 4,5 through other optoelectronic and thermoelectronic devices [6][7][8] to inorganic-organic transistors 9 are at the center of interest.…”