Supersensitization of CdS Quantum Dots with a Near-Infrared Organic Dye: Toward the Design of Panchromatic Hybrid-Sensitized Solar Cells

Abstract

The photoresponse of quantum dot solar cells (QDSCs) has been successfully extended to the near-IR (NIR) region by sensitizing nanostructured TiO(2)-CdS films with a squaraine dye (JK-216). CdS nanoparticles anchored on mesoscopic TiO(2) films obtained by successive ionic layer adsorption and reaction (SILAR) exhibit limited absorption below 500 nm with a net power conversion efficiency of ~1% when employed as a photoanode in QDSC. By depositing a thin barrier layer of Al(2)O(3), the TiO(2)-CdS films were further modified with a NIR absorbing squaraine dye. Quantum dot sensitized solar cells supersensitized with a squariand dye (JK-216) showed good stability during illumination with standard global AM 1.5 solar conditions, delivering a maximum overall power conversion efficiency (η) of 3.14%. Transient absorption and pulse radiolysis measurements provide further insight into the excited state interactions of squaraine dye with SiO(2), TiO(2), and TiO(2)/CdS/Al(2)O(3) films and interfacial electron transfer processes. The synergy of combining semiconductor quantum dots and NIR absorbing dye provides new opportunities to harvest photons from different regions of the solar spectrum.

Ultrafast characterization of the electron injection from CdSe quantum dots and dye N719 co-sensitizers into TiO2 using sulfide based ionic liquid for enhanced long term stability

“…8,9 In addition, semiconductor QDs are excellent building blocks for the design of light supracollecting structures by the synergetic combination of different types of QDs, 10,11 or QDs and dyes. [12][13][14][15][16][17][18][19][20] Different QDs and dye hybrid systems have been explored with the aim to exploit their interacting proprieties. In this heterostructures, performance can arise from the fast scavenging of photogenerated holes in quantum dots by a molecular dye.…”

“…15,19 Simultaneously, the combined use of QD and dye enhances the light harvesting wavelength range due to the combined absorption of the two assembled sensitizers. 12,17,18 Although hybrid sensitized systems appear promising, only few examples have been…”

Super Sensitization: Grand Charge (Hole/Electron) Separation in ATC Dye Sensitized CdSe, CdSe/ZnS Type‐I, and CdSe/CdTe Type‐II Core–Shell Quantum Dots

“…Hence, people are considering the design and development of quantum dot sensitized solar cells (QDSSC) for the next generation of solar modules. [2][3][4] In this regard, research on multiple exciton generation (MEG) in quantum dots [5][6][7] has been increased manifold as it is believed that a single photon can generate more than one electron-hole pair which in turn can drastically increase the efficiency of the devices. It has been realized and partially verified that the efficiency of quantum dot solar modules can be enhanced significantly by dissociating or separating the multi-exciton before ultrafast exciton-exciton annihilation.…”

Fabrication and characterization of nanowalls CdS/dye sensitized solar cells

“…Mali and coworkers [14] found that the efficiency for TiO 2 microspheres covered by CdS nanoparticles reached 2.34%, while Choi et al [15] obtained 3.14% from the device that they synthesized, based on TiO 2 /CdS quantum dots. Moreover, Meng et al [16] prepared devices with ZnO spheres/CdS quantum dots and obtained an efficiency of about 1.39%.…”