Via pv-tech. Brief note on efficiency record: Solarmer has managed to get an (NREL certified) power conversion efficiency of 7.9% for an organic solar cell… sounds good, and broke the recent record (by the same company). It is important to mention, though, that the active area was very small with 0.1cm2 (aperture 0.047cm2).
4 thoughts on “Towards ten percent… Solarmer hits 7.9% with plastic solar cell”
Hello, Can I ask something, As far as I know, the highest efficiency of organic-inorganic BHJ solar cell is around 2.8% (CdSe tetrapod/OC1C10-PPV), what is factor limiting this approach compare to P3HT-PCBM despite its advantages?
Hi! My take: the limited efficiency of organic-inorganic hybrid solar cells is mainly due to the donor-acceptor phase separation. Fortunately, this is not an ultimate limit. Also, charge transfer etc seem to work fine, and charge separation might be improved due to the higher dielectric constant of the inorganic acceptor. So if someone (you?! ;-) manages to optimise the spatial dimensions of the phase segregation properly, I believe that a couple of percent point more should be possible.
Hi, thanks for your answer. I agree that phase separation is a big issue here, but I think the wide band gap material of CdSe is also a limitation. But then I observe that the hybrid solar cell using narrow band gap such as PbSe, PbS even have smaller PCE. It’s probably because the phase separation issue, but perhaps the band alignment also not favorable for the photoinduced charge transfer. What is your opinion?
nb:I really like your blog, keep it up, It’s open my eyes, ;-),
I found that you were working in IMEC with Prof. Paul Heremans, He will become my co-promotor for my PhD at KUL.
Hi! Thanks:-) And sorry for the later answer…finished a review today, and tomorrow is an important project review. So brief comment only for now, hope you understand.
I have never investigated hybrids myself, and have only limited insight. If you look at the systems around, it seems to me that charge transfer itself works… at least for the hybrids with beyond 2% efficiency;-) The open circuit voltage is sometimes better than for polymer:fullerene systems. Taking one example, CdSe/APFO-3, which had a short circuit current density of 7.2 mA/cm2 (EQE 40%) and an open circuit voltage of almost 1 V… [Wang 2006]. Everything is ok, even PL quenching, only the fill factor is a bit low. Therefore, I believe in the morphology as major reason. (What I do not know, though, is how unbalanced the electron and hole mobilities are…) The question is, can it be better controlled, or can modification of either donor or functionalisation of the inorganic help in optimising it? To me, there is no fundamental reason that hybrids should not be beyond 5%!
Greetings to Paul, and good luck;-) and success to you!