Integration of polyelectrolyte based electrochromic material in printable photovoltaic electrochromic module

• Printable PV-EC module integrates planar structure Si-TFSCs with PANI/PSS NSTF.
• The PANI/PSS NSTF on the anode undergoes oxidation reaction under sunlight.
• The NSTF darkens in 18.1 min and bleaches in 38.1 min with ΔT of 34% at 655 nm.

Compared to traditional electrochromic technology, photovoltaic electrochromic (PV-EC) module can achieve color change in electrochromic layers without additional power source. In this work, an innovative printable PV-EC module is provided. The device includes a plurality of planarly distributed silicon thin film solar cells (Si-TFSCs) configured in superstrate structure, covered with a layer of polyelectrolyte based electrochromic thin film (ECTF). The Si-TFSC consists of one anode (with a portion of area exposed from the Si-TFSC), a photoelectric conversion layer, and one cathode. The ECTF is prepared from nano-size polyelectrolyte based electrochromic material, which is composed of polyaniline (PANI) and polyanion poly(sodium 4-styrenesulfonate) (PSS) nanospheres mixture. When the printable PV-EC module is irradiated by sunlight, the PANI/PSS ECTF on the surface of the transparent anode layer exhibits anodic color changing, and transforms from pale green (emeraldine salt state) to light blue (emeraldine blue state).