Choodam K.Kamjam N.Sukpan N.Seriwattanachai C.Inna A.Shin Thant K.K.Srathongsian L.Supruangnet R.Nakajima H.Kaewprajak A.Kumnorkaew P.Wongratanaphisan D.Ruankham P.Pakawatpanurut P.Kanjanaboos P.Mahidol University2026-02-062026-02-062026-01-01Small Science Vol.6 No.1 (2026)https://repository.li.mahidol.ac.th/handle/123456789/114512Perovskite solar cells (PSCs) are emerging as a promising technology for indoor photovoltaics due to their high efficiency and cost-effective manufacturing. In this article, three strategies are explored to reduce costs and enable perovskite materials (PSK) as power sources for indoor internet of things (IoTs): 1) using dual perovskite absorber layer (PSK1/polyethylene glycol (PEG)/PSK2) to replace both the absorber and hole transport layers, 2) utilizing spray-coating for perovskite deposition under ambient conditions with 45%–65% relative humidity (RH), and 3) replacing metal electrodes with carbon electrodes. The dual absorber layer improves charge transport, while the spray-coating process minimizes solution waste, making large-scale production more feasible. Additionally, the use of PEG as an interlayer effectively enhances defect passivation, improving charge transport and stability. The proposed carbon-based device architecture offers the lowest material cost ($11.98 m⁻²) and the modified levelized cost of electricity for indoor light (m-LCOE-i) of 1.54 ¢ Wh⁻¹, outperforming traditional Spiro-OMeTAD/Au or carbon designs along with enhancing the commercial viability of PSCs. To demonstrate its practicality, connected PSCs are utilized to power IoT devices for over a month under typical laboratory lighting conditions (300–400 lux) at 40%–65% RH.Materials ScienceChemical EngineeringArticleSCOPUS10.1002/smsc.2025004512-s2.0-10502787974026884046