Revival of Solar Paint Concept: Air-Processable Solar Paints for the Fabrication of Quantum Dot-Sensitized Solar Cells

Abstract

One way to revolutionize solar energy production and expand it to a large scale is to reduce the manufacturing cost and complexity of the fabrication process. The ability to make solar cells on the surface of any shape would further transform this technology. Quantum dot-sensitized solar cells (QDSSCs) are an ideal candidate to push solar cell technology in this direction. In this regard, making a paint that can be applied by a paint brush to any transparent conductive surface to turn it into the photoanode of QDSSCs is the ultimate goal. We herein demonstrate the feasibility of one-coat fabrication of QDSSCs from a lead sulfide (PbS)-based solar paint. This is possible because of its unique ability to regenerate after oxidation occurred during heat treatment in air. Hence, the whole fabrication process can be carried out in air unlike a first-generation solar paint based on cadmium sulfide (CdS) and cadmium selenide (CdSe). Two solar paints using a commercially available titanium dioxide (TiO 2 ) and a p-type TiO 2 powder were synthesized and evaluated. Also, the performance-limiting parameters are thoroughly investigated using various spectroscopic and electrochemical characterization methods. The implication of new insights into the PbS-based solar paint for further development of paint-on solar cells is discussed.

Interfacial Engineering at Quantum Dot-Sensitized TiO2 Photoelectrodes for Ultrahigh Photocurrent Generation

“…This may be partly related to the ultrafast electron injection rate of QDs caused by the direct deposition method. 54 The increased density of surface states induced by the SPL facilitated multiple trapping transport, which was demonstrated by the improvement of the chemical diffusion coefficient. The facilitated multiple trapping/detrapping transport along with morphological changes of the mesoporous TiO 2 films (related to increased N ) increased the electron conductivity of TiO 2 films.…”

“… 24 Therefore, the reason for the above results is more likely due to electron injection from PbS QDs to the TiO 2 film in the ultrafast range of femtoseconds. 54 …”

“…This may be partly related to the ultrafast electron injection rate of QDs caused by the direct deposition method. 54 …”

Overcoming the Ambient Manufacturability‐Scalability‐Performance Bottleneck in Colloidal Quantum Dot Photovoltaics

“…For these reasons, CQD solar cells fabricated under humid ambient conditions are of particular interest, as are those translated into large‐area compatible, high‐throughput fabrication techniques. A low‐cost PV technology aiming at industrial implementation in ambient air will need to be invariant under moisture conditions during manufacture and utilization . In contrast with this requirement, today's best cells—if they are to be manufactured year‐round in a wide range of geographies—require careful and costly environment control during manufacture .…”

Solar Paint from TiO2 Particles Supported Quantum Dots for Photoanodes in Quantum Dot–Sensitized Solar Cells

“…34 During the preparation of this article, Bang and co-workers increased the highest PCE to 1.35% through this solar paint route with use of PbS QDs as the light-harvesting material. 35 However, all of these reported solar paint approaches to fabricate the photoanode applied the successive ion layer absorption and reaction method to deposit QDs on the TiO 2 substrate. As discussed above, this in situ growth method usually resulted in the high density of trap state defects and heterogeneous size distribution of the formed QDs, seriously deteriorating photovoltaic performance of the cell devices.…”