The subject of the present invention relates to a high efficiently dielectric barrier discharge (DBD)-lamp for generating and/or emitting a radiation of ultraviolet (UV)-light comprising: a discharge gap (1) being at least partly formed and/or surrounded by at least an inner wall (2) and an at least partly transparent (3), each with an inner surface (2a, 3a), facing the discharge gap (1) and an outer surface (2b, 3b) arranged opposite of and directed away from the corresponding inner surface (2a, 3a), a filling located inside the discharge gap (1), at least two electrical contacting means (4), a first electrical contacting means (4a) at the inner wall (2) and a second electrical contacting means (4b) at the outer wall (3), and at least one luminescent coating layer (5) arranged at/on and at least partly covering at least a part of the respective wall's inner surface (3a), arranged such, that at least a part of the generated UV-light of a certain wavelength range can pass the luminescent coating layer (5) from the discharge gap (1) to the outside of the DBD-lamp, whereby at least one of both walls (2, 3) is at least partly arranged with directing means (6), so that the diffusive radiation is directed in direction through the transparent part of the outer wall (3) with reduced losses due to absorption effects and the like.