Jingchao's work is accepted in Joule

We report a facile and versatile method of acquiringstable organic photovoltaics via vacuum stress assisted thermal annealing(VTA). Through comprehensive X-ray diffraction and scattering techniques, we demonstrate that VTA not only can restrain the over growth of photovoltaic molecules and lead to slender fibrillar networks, but also can reduce the free volume of the photoactive layer leading to slower structural relaxation during operation which enable a predicted T80 lifetime over 30 years.