[Sample B: Approval/Signature Sheet]

Unfortunately, TIPS-pentacene has a reaction with fullerene derivatives, resulting in
inefficient photoinduced charge transfer. The optimized efficiency was around 0.5%.
Recently, researchers have made progress on 3,6-diaryl-2,5-dihydro-pyrrolo-[3,4-
c]pyrrole-1,4-dione (DPP)-based materials [36]. By replacing bithiophene with a
benzofuran substituent, the DPP-based molecules have increased intermolecular
chromophore interaction through high conjugation. With an optimized ratio of PC 70 BM,
the as-cast blend film had very little phase separation. Upon thermal annealing, the
surface of the film roughens and shows distinct donor and acceptor domains, resulting in
well-controlled phase separation of the DPP-based donor and PC 70 BM acceptor. The
deep HOMO band of the donor material yields an increased V oc =0.9V, J sc =10 mA/cm 2 ,
FF = 0.48, an optimized device efficiency of 4.4%[36].
Several groups have explored a variety of other materials over the past few years
including several well-known classes of dye molecules such as borondipyrromethene
(BODIPY) [37], merocyanine[38] and squaraine[39]. For soluble small molecule bulk HJ
solar applications, these dye materials have been functionalized with solubilizing groups.
Squaraines are the condensation products of squaric acid and two equivalents of a
suitable electron-rich precursor. They are a class of functional organic dyes for a variety
of electronic and photonic applications such as imaging, nonlinear optics, photovoltaics,
photodynamic therapy and ion sensing [40]. From the standpoint of their electronic
properties, squaraines are highly delocalized conjugated molecules possessing a cyaninelike
structure. Their most notable features are that they have sharp and intense absorption
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