  Ultrathin, solution-processed emerging solar cells with high power-per-weight
(PPW) outputs demonstrate unique potential for applications where low weight,
high power output, and flexibility are indispensable. The following perspective
explores the literature of emerging PVs and highlights the maximum reported PPW
values of Perovskite Solar Cells (PSCs) 29.4 W/g, Organic Solar Cells (OSCs)
32.07 W/g and Quantum Dot Solar Cells (QDSC) 15.02 W/g, respectively. The
record PPW values of OSCs and PSCs are approximately one order of magnitude
higher compared to their inorganic ultrathin solar cells counterparts (approx.
3.2 W/g for CIGS and a-Si). This consists emerging PVs, very attractive for a
variety of applications where the PPW is the key parameter. In particular, both
OSCs and PSCs can be implemented in different scenarios of applications (indoor
and biocompatible applications for OSCs and outdoor and high-energy radiation
conversion conditions for the PSCs) due to their unique optoelectronic and
physiochemical properties. Finally, our theoretical optical and electrical
simulation and optimization study for the most promising and well-suited PV
technologies, showed an impressive maximum realistic theoretical PPW limit of
74.3 and 93.7 W/g for PSCs and OSCs, respectively. Our finding shows that the
literature PSCs and OSCs towards high PPW outputs, is not quite close to the
theoretical maximum and thus more work needs to be done to further increase the
PPW output of these promising PV technologies.
