Metal-Cluster-Sensitized Solar Cells. A New Class of Thiolated Gold Sensitizers Delivering Efficiency Greater Than 2%

Abstract

A new class of metal-cluster sensitizers has been explored for designing high-efficiency solar cells. Thiol-protected gold clusters which exhibit molecular-like properties have been found to inject electrons into TiO2 nanostructures under visible excitation. Mesoscopic TiO2 films modified with gold clusters deliver stable photocurrent of 3.96 mA/cm(2) with power conversion efficiencies of 2.3% under AM 1.5 illumination. The overall absorption features and cell performance of metal-cluster-sensitized solar cells (MCSCs) are comparable to those of CdS quantum-dot-based solar cells (QDSCs). The relatively high open-circuit voltage of 832 mV and fill factor of 0.7 for MCSCs as compared to QDSCs show the viability of these new sensitizers as alternatives to semiconductor QDs and sensitizing dyes in the next generation of solar cells. The superior performance of MCSCs discussed in this maiden study lays the foundation to explore other metal clusters with broader visible absorption.

Quantum coherent plasmon in silver nanowires: A real-time TDDFT study

“…[11][12][13][14][15][16] Applications include high-sensitivity chemical and biological sensing [17][18][19][20][21][22][23][24][25] as well as energy conversion and storage. 26,27 Anisotropic systems such as nanorods and nanowires are especially useful for certain applications such as photothermal cancer therapy. 28,29 Noble metal nanorods have two main plasmon modes: the longitudinal mode (along the main axis of the nanorod) and the transverse mode (in the plane perpendicular to the main axis).…”

Effect of the electrophoretic deposition of Au NPs in the performance CdS QDs sensitized solar Cells

“…To do appropriate fit the EIS measurements, the equivalent circuit shown in Figure 6 was used [29,50,53,54]. The chemical capacitance is proportional to the density of states (DOS) in the band gap, DOS increases exponentially with the proximity to the conduction band (CB), then, an increase in C µ suggest a displacement to lower energies of the TiO 2 CB.…”

“…[3, [21][22][23][24][25][26][27][28] However, mechanistic evidence that directly supports electron transfer arising from plasmon excitation remains elusive. [3, 29,30] However, a strong increase in photoconversion efficiency with QD-sensitized Au-TiO 2 NP composite have been found which was attributed to enhanced absorption of QDs caused by increased scattering of light by the Au NPs [13,17]. Other authors, had found that Au NPs act as electron traps to help separate the photogenerated charges and subsequently improve interfacial charge transfer [10,16,[31][32][33].…”

“…[3,5,13-20] EIS can identify important parameters affecting the cell performance, such as: (i) electron transport in the TiO 2 , which is influenced by the free carrier density and electron mobility, the latter being likely dependent on the carrier density, as the electron motion is a trap limited process,[3, [21][22][23][25][26][27][28] (ii) transfer of electrons to redox species in the electrolyte (sometimes named recombination or back reaction process in the context of DSSC studies), (iii) charging of the contact on the transparent conducting substrate (TCS) with the electrolyte (provided that the electrolyte penetrates the porous structure up to the substrate), and (iv) charging of capacitive elements in the high surface area porous structure, including the Helmholtz capacitance in the TiO 2 /electrolyte interface and the capacitances related to filling of the conduction band and surface states of the TiO 2 in the porous structure. [3, 29,30] In addition, the lifetime, the diffusion coefficient, and the diffusion length could be obtained [13,17].…”

Density-functional theory study of ionic inhomogeneity in metal clusters using SC-ISJM

“…Nowadays, due to the significant progress in the experimental methods, it is possible to synthesize clusters with some desired properties. Among the various types of clusters, metal clusters (MC) are of much interest, firstly because of their biological and technological applications, [20][21][22][23][24][25][26][27][28][29][30] and secondly because the theoretical description of metallic systems are relatively simple.…”