respectively. The red-shifted PL peak of the graphene-PbS QD composite is attributed not only to photoinduced charge transfer but also to the spontaneous doping effect of the PbS QDs due to the transferred carriers between them and graphene^[@CR30]^. The PL intensities of the graphene-PbS QD composites with 25% and 50% graphene were lesser by 24.3% and 37.2%, respectively, compared to that of the PbS QDs. The PL intensity represents the number of recombined carriers in the PbS QDs for a unit amount of QDs. These quenched PL intensities are attributed to the enhanced transfer of the photoinduced carriers between graphene and the PbS QDs, which minimizes the charge recombination rate. In addition, Fourier-transform infrared spectroscopy establishes that hexane solution and the glass substrate do not affect the opticalA 1,800-year-old triumphal arch destroyed by Isis in the Syrian city of Palmyra last year is rising again in London.

The recreation of Palmyra’s Arch of Triumph will stand for four days in Trafalgar Square after being made by carving stone to the exact shape of the original, working from a database of 3D photographs collected by the Institute of Digital Archaeology (IDA).

After its stay in London – which has been timed to coincide with World Heritage Week - the recreated arch will be taken around the world, visiting New York’s Times Square and Dubai, before being taken to Syria.

Maamoun Abdulkarim, Syria’s director-general of antiquities and museums, who was in London to watch the £100,000, 12-ton, scale model being installed, said: “It is a message of raising awareness in