| Title | Linking Vertical Bulk-Heterojunction Composition and Transient Photocurrent Dynamics in Organic Solar Cells with Solution- Processed MoO x Contact Layers |
| Publication Type | Journal Article |
| Year of Publication | 2014 |
| Authors | B.J.T. de Villers, Roderick C. I. MacKenzie, J.J. Jasieniak, N.D. Treat, and M.L. Chabinyc |
| Journal | ADVANCED ENERGY MATERIALS |
| Volume | 4 |
| Pagination | 1301290 |
| Date Published | APR |
| ISSN | 1614-6832 |
| Keywords | drift-diffusion, metal oxide, molybdenum oxide, organic solar cells, photocurrent dynamics, solution processing |
| Abstract | It is demonstrated that a combination of microsecond transient photocurrent measurements and film morphology characterization can be used to identify a charge-carrier blocking layer within polymer:fullerene bulk-heterojunction solar cells. Solution-processed molybdenum oxide (s-MoOx) interlayers are used to control the morphology of the bulk-heterojunction. By selecting either a low- or high-temperature annealing (70 degrees C or 150 degrees C) for the s-MoOx layer, a well-performing device is fabricated with an ideally interconnected, high-efficiency morphology, or a device is fabricated in which the fullerene phase segregates near the hole extracting contact preventing efficient charge extraction. By probing the photocurrent dynamics of these two contrasting model systems as a function of excitation voltage and light intensity, the optoelectronic responses of the solar cells are correlated with the vertical phase composition of the polymer:fullerene active layer, which is known from dynamic secondary-ion mass spectroscopy (DSIMS). Numerical simulations are used to verify and understand the experimental results. The result is a method to detect poor morphologies in operating organic solar cells. |
| DOI | 10.1002/aenm.201301290 |
