کنفرانس سلول های خورشیدی نانوساختاری

کارگاه ساخت و آنالیز سلول های خورشیدی

همه ساله در روز پس از کنفرانس و در راستای ارتقای سطح علمی محققین در زمینه فناوری سلول‌های خورشیدی نانوساختاری،‌ کارگاهی یک روزه برگزار می شود. در این کارگاه ها جنبه های عملی تر فناوری مورد بحث قرار می گیرند.

زمان: 1 دی ماه 1396، ساعت 08:30 تا 17:00
مکان: دانشگاه صنعتی شریف، دانشکده فیزیک
1- Measuring charge generation in organic D/A solar cells; on the role of carrier mobility
دکتر صفا شعاعی / دانشگاه پتسدام، آلمان
ساعت 08:30 تا 10:00
Several analytical relations have been proposed in the past to connect the efficiency of free charge generation, recombination and extraction to bulk mobilities, but the dynamic and steady state properties of functioning bulk heterojunction cells seem to remain partially inconsistent with the predictions of these models. This might not come as a surprise when considering the different length and time scales at which these three processes occur. Time resolved mobility studies confirm a significant mismatch between the initial / local mobilities obtained by THz or TREFISH / TRMC in BHJ layers, and the bulk mobilities as obtained by conventional electro-optical transient techniques, such as time of flight or space charge limited current measurements. This can be rationalized through the highly complex and heterogeneous energetic landscape and morphology for carrier motion in multicomponent layers of organic semiconductors which lack long-range order. This translates into a significant number of trap states-from which a carrier can escape by thermal excitation only - deteriorating the overall bulk mobility by orders of magnitude compared to the charges’ intrinsic hopping rates on nm-length scales. Time dependent measurements show that the carrier mobility is strongly time dependent, originating from the relaxation in the density of states. TAS, TRMC, THz and TREFISH all point to similar local carrier mobility values on the order of 0.1 cm2V-1s-1, when similar separation distances or timescales relevant for CT dissociation are considered. This makes it important to note precisely the timescale that is critical for dissociation of photogenerated charges, to distances where their Coulomb attraction is overcome.