Comments on Device Optimization

It is also important to note the effect of device architecture. In the case of compounds 36 and 37, the use of the standard hole transport material (HTL) PEDOT PSS led to devices with low PCE. Use of metal oxide HTLs (nickel oxide or molybdenum oxide) significantly improved device performance by greater than 100%, and allowed for record efficiencies to be achieved. For compound 41, employinginverted device architectures, zinc oxide optical spacers, polyelectrolyte interlayers, and barium cathodes, all led to significant improvements in device PCE, with a record 9% being achieved.  

To this end, while innovative molecular design has led to the realization of small molecule donors with ideal optical and electronic properties, and the ability to form uniform thin-films from solution, these molecules must not be treated like polymers when considering the fabrication of BHJ solar cells. It almost all reports, D A ratios greater than 1 and the use of processing 

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