An inverted polymer photovoltaic cell with increased air stability obtained by employing novel hole/electron collecting layers

Abstract

In this work, an inverted device was fabricated using titania (TiO 2 ) as the electron collecting layer (ECL) and sulfonated poly(diphenylamine) (SPDPA) as the hole collecting layer (HCL). Smooth TiO 2 film with good electron collecting ability was easily formed using the spin-coating process. The power conversion efficiency (PCE) was 3.91%, the same as that of a conventional device. This inverted device is ascertained to maintain 2.82% PCE after 400 h of air-storage. Because of the appropriate work functions of ECL and HCL, the interfaces at the active layer have the ohmic contacts those approach the ideal value of open circuit voltage. SPDPA helps improve the interfacial dipole effect between the active layer and the metal, as verified by in-situ ultraviolet photoelectron spectroscopic data.

Dielectric Interface Effects on Surface Charge Accumulation and Collection towards High-Efficiency Organic Solar Cells

“…6 The TiO x was prepared by spin-coating Ti(OC 3 H 7 ) 4 on top of ITO glass in nitrogen gas filled glovebox, then underwent hydrolysis and was transferred to TiO x in air for 1 h. After 1 h, the TiO x film was thermally annealed at 450 C for 30 min. 35 dissolving zinc acetate dehydrate into a mixed solvent of 2-methoxyethanol and 0.1M acetic acid aqueous solution at a 1: 1 volume ratio with a solution concentration of 0.1 g/ml. The solution was spin-coated on top of ITO glass, then underwent thermal annealing for 450 C for 30 min.…”

Enhanced Power-Conversion Efficiency in Inverted Bulk Heterojunction Solar Cells using Liquid-Crystal-Conjugated Polyelectrolyte Interlayer

“…[1][2][3] Recently, highly effective polymer solar cells have been obtained with an inverted device configuration using high work-function anode (e.g., Au, Ag) to collect holes and modified indium tin oxide (ITO) as the cathode to collect electrons. 4 Compared to the traditional PSCs, inverted devices present superior long-term humid stability by averting the usage for the hygroscopic and corrosive hole-transmission layer material poly (3,4-ethylenedioxylenethiophene):poly(styrenesulphonic acid) (PEDOT:PSS) and…”

Low-Temperature, Chemically Grown Titanium Oxide Thin Films with a High Hole Tunneling Rate for Si Solar Cells

“…To determine the proper band alignment to n-type Si for carrier selection, ultraviolet (UV) photoemission spectroscopy (UPS) was performed to measure the energy levels of TiO 2 [20]. The UPS was performed by emitting UV photons with an energy of 21.2 eV to the TiO 2 film.…”

“…The maximum BE was obtained at zero KE, as shown in Figure 1b. The work function (Φ) of the films was defined by Φ = hυ´∆E, in which ∆E is determined as the BE at the cutoff edge of electron emission [20,21]. Extrapolation shows that the cutoff edge is 17 eV.…”