Interfacial Depletion Regions: Beyond the Space Charge Limit in Thick Bulk Heterojunctions.
ACS Appl Mater Interfaces
; 8(3): 2211-9, 2016 Jan 27.
Article
em En
| MEDLINE
| ID: mdl-26690662
ABSTRACT
Space charge limited photocurrent is typically described as the limiting factor in carrier extraction efficiency for organic bulk heterojunctions with increasing thickness. It successfully characterizes the carrier extraction efficiency in these devices with thin to moderate thickness and dissimilar carrier mobilities. However, in this article we show that space charge limited photocurrent cannot solely explain the intensity dependent spectral response of extremely thick organic photovoltaics. In addition, interfacial depletion regions near the contacts contribute to the field distribution and carrier collection. Here, we describe charge collection efficiency with an optical p-i-n model, allowing for collection from band bending due to mobility-induced and interfacial-doping-induced space charge regions. We verify the model with up to 1400 nm thick spray-coated devices in both p-i-n (conventional) and n-i-p (inverted) architecture, including variations of thickness, illumination intensity, transport materials, and bifacial (semitransparent) devices.
Texto completo:
1
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article